<PAGE>

                                                                    EXHIBIT 10.1

================================================================================



                          STAND-BY PURCHASE AGREEMENT

                                    BETWEEN

                           RAMIUS CAPITAL GROUP, LLC

                                      AND

                           ONYX SOFTWARE CORPORATION


                                JANUARY 4, 2001



================================================================================

                 PROVISIONAL PATENT APPLICATION HAS BEEN FILED
<PAGE>

                               TABLE OF CONTENTS
                               -----------------
<TABLE>
<CAPTION>
                                                                                                                                Page
                                                                                                                                ----
<S>    <C>                                                                                                                      <C>
I.     DEFINITIONS ..............................................................................................................  1

II.    PURCHASE AND SALE OF COMMON STOCK ........................................................................................  2
       2.1 Investments ..........................................................................................................  2
       2.2 Limitations on Investment Amount .....................................................................................  2
       2.3 Closings and Settlements .............................................................................................  2
       2.4 Termination, Suspension and Modification of Investment Obligation ....................................................  3

III.   CONDITIONS PRECEDENT......................................................................................................  3
       3.1 Conditions Precedent to the Obligation of the Investor to Purchase Common Stock Pursuant to a Capital Demand Notice ..  3
       3.2 Occurrence of Material Events ........................................................................................  4
       3.3 Due Diligence Review .................................................................................................  4

IV.    REPRESENTATIONS AND WARRANTIES OF INVESTOR ...............................................................................  4
       4.1 Authorization; Enforcement ...........................................................................................  4
       4.2 Not an Affiliate .....................................................................................................  5
       4.3 Organization and Standing ............................................................................................  5
       4.4 Absence of Conflicts .................................................................................................  5

V.     REPRESENTATIONS AND WARRANTIES OF THE COMPANY ............................................................................  5
       5.1 Representations and Warranties Incorporated By Reference .............................................................  5

VI.    COVENANTS ................................................................................................................  5
       6.1 Covenants Incorporated By Reference ..................................................................................  5
       6.2 Short Selling ........................................................................................................  5

VII.   ASSIGNMENT, ENTIRE AGREEMENT, AMENDMENT, TERMINATION .....................................................................  5
       7.1 Successors and Assigns ...............................................................................................  5
       7.2 Entire Agreement; Amendment ..........................................................................................  6
       7.3 Publicity ............................................................................................................  6
       7.4 Termination ..........................................................................................................  6

VIII.  NOTICES; COSTS AND EXPENSES ..............................................................................................  8
       8.1 Notices ..............................................................................................................  8
       8.2 Costs and Expenses ...................................................................................................  9

IX.    INDEMNIFICATION AND CONTRIBUTION .........................................................................................  9
       9.1 Indemnification ......................................................................................................  9
       9.2 Contribution ......................................................................................................... 11
</TABLE>

                                       i
<PAGE>

<TABLE>
<S>   <C>                                                                                                                        <C>
X.     GOVERNING LAW; MISCELLANEOUS ............................................................................................. 11
       10.1 Governing Law ....................................................................................................... 11
       10.2 Counterparts ........................................................................................................ 12
       10.3 Headings............................................................................................................  12
       10.4 Severability........................................................................................................  12
       10.5 Survival............................................................................................................  12
       10.6 No Third Party Beneficiaries........................................................................................  12
       10.7 Further Assurances..................................................................................................  12
       10.8 Construction........................................................................................................  12
       10.9 Equitable Relief....................................................................................................  12
       10.10 Consent to Jurisdiction............................................................................................  13
</TABLE>

                                       ii
<PAGE>

                               CROSS REFERENCES
                               ----------------

Defined Term
------------

"Agreement"                                                   Preamble
"Blocking Event"                                              Section 2.4
"Buy-In Actual Damages"                                       Section 2.3
"Claims"                                                      Section 9.1(a)
"Closing Date"                                                Section 1
"Common Stock"                                                Recitals
"Company"                                                     Preamble
"Condition Precedent Date"                                    Section 3.1
"DTC"                                                         Section 2.3(a)
"Indemnified Damages"                                         Section 9.1(a)
"Indemnified Party"                                           Section 9.1(b)
"Indemnified Person"                                          Section 9.1(a)
"Investor"                                                    Preamble
"Notice of Blocking Period"                                   Section 3.2
"Notification Date"                                           Section 1
"Permitted Transferee"                                        Section 7.1
"Purchase Price"                                              Section 1
"Registrable Securities"                                      Section 1
"Registration Statement"                                      Section 2.4(a)(i)
"SEC"                                                         Section 2.4
"Settlement"                                                  Section 2.3(a)
"Settlement Date"                                             Section 1
"Underwriter"                                                 Recitals
"Underwriting Agreement"                                      Recitals
"Violations"                                                  Section 9.1(a)
<PAGE>


                          STAND-BY PURCHASE AGREEMENT
                          ---------------------------

          STAND-BY PURCHASE AGREEMENT dated as of January 4, 2001 (the
"Agreement"), between Ramius Capital Group, LLC, a limited liability company
organized and existing under the laws of the State of Delaware (the "Investor"),
and Onyx Software Corporation, a corporation organized and existing under the
laws of the State of Washington (the "Company").

                             W I T N E S S E T H :

          WHEREAS, pursuant to the Common Stock Underwriting Agreement between
Ramius Securities, LLC (the "Underwriter") and the Company dated as of the date
hereof (the "Underwriting Agreement"), the Underwriter agreed to sell, as the
Company's agent, on a best efforts basis, up to $30 million of the Company's
Common Stock, $.01 par value per share (the "Common Stock");

          WHEREAS, upon the terms and subject to the conditions of this
Agreement, should the Underwriter fail to fulfill its Selling Period Obligation
then the Investor shall be obligated to purchase the number of shares of the
Company's Common Stock necessary to fulfill the Underwriter's Selling Period
Obligation;

          WHEREAS, terms used in this Agreement without being specifically
defined herein shall have the meanings set forth in the Underwriting Agreement.

          NOW, THEREFORE, the parties hereto agree as follows:

I.  DEFINITIONS.

          Capitalized terms not defined herein shall have the same meaning
ascribed to them in the Underwriting Agreement. As used in this Agreement, the
following terms shall have the following meanings:

          "Closing Date" shall mean, with respect to the purchase and sale of
Common Stock subject to the conditions contained herein, the First Trading Day
following the expiration of the Selling Period if the Underwriter fails to
fulfill its Selling Period Obligation for such Selling Period.

          "Purchase Price" shall mean 96.5% of the VWAP for the first Trading
Day following the expiration of the Selling Period; provided, that if the VWAP
for such Trading Day is at or below the Floor Price, the VWAP for such day shall
be deemed to be the Floor Price.

          "Registrable Securities" shall mean any shares of Common Stock issued
or issuable to the Investor or any holder or transferee pursuant to this
Agreement and any shares of Capital Stock issued or issuable with respect to the
foregoing as a result of any stock split, stock dividend, recapitalization,
exchange or similar event.

          "Registration Statement" shall mean a registration statement of the
Company, as amended or supplemented from time to time, relating to (i) Common
Stock issuable pursuant to the Underwriting Agreement (including shares of
Common Stock issuable in connection with the exercise of the Purchase Option)
and (ii) Common Stock issuable pursuant to this Agreement.

          "Settlement Date" shall mean, with respect to the purchase and sale of
Common Stock, subject to the conditions contained herein, the Trading Day no
later than three days (or such lesser time
<PAGE>

period as is mandated under "regular ways" settlement on the Principal Market)
following the Closing Date.

II.  PURCHASE AND SALE OF COMMON STOCK.
     ---------------------------------

          2.1  Investments.  If pursuant to the terms and conditions of the
Underwriting Agreement, the Company delivers a Capital Demand Notice to the
Underwriter and the Underwriter fails to fulfill its Selling Period Obligation,
then the Investor, subject to the terms and conditions of this Agreement, shall
be obligated to purchase from the Company the number of shares of Common Stock
necessary to fulfill the Underwriter's Selling Period Obligation.

          2.2  Limitations on Investment Amount.

          (a)  Selling Period Obligation.  The Investor's obligation to purchase
shares of the Company's Common Stock shall be null and void if (i) a Blocking
Event occurs (as provided in Section 2.4); or (ii) the remaining Selling Period
Obligation multiplied by the Purchase Price is less than $100,000. The Investor
may waive, in its sole discretion, in whole or in part, the limitations on the
Investor's obligations to purchase shares of Common Stock contained in this
Section 2.2(a).

          (b)  4.9% Limit.  Notwithstanding anything herein to the contrary, the
Investor shall not be required nor allowed to purchase, and the Company shall
not issue, shares of Common Stock pursuant to this Agreement on the Closing Date
to the extent such purchase, when aggregated with all other shares of Common
Stock then beneficially owned by the Investor, would result in the Investor or
any Affiliate of the Investor beneficially owning more than 4.9% of all the
issued and outstanding Common Stock of the Company on such Closing Date. For
purposes of this Agreement, beneficial ownership shall be calculated in
accordance with Section 13(d) of the Exchange Act.

          2.3  Closings and Settlements.

          (a)  Deliveries.  On the Settlement Date (i) the Company shall credit
such aggregate number of shares of Common Stock that the Investor had purchased
on the Closing Date to the Investor's or its designee's balance account with The
Depository Trust Company ("DTC") through its Deposit and Withdrawal At Custodian
system or deliver such shares by such other means as may be mutually agreed by
the parties; and (ii) if such shares are so received no later than 1:00 p.m.
Eastern time, the Investor shall deliver to the Company's brokerage account at
the Underwriter, (or if later than 1:00 p.m. Eastern time, in funds available
the next Trading Day) on or prior to the Settlement Date, a dollar amount equal
to (A) the number of shares so received multiplied by (B) the Purchase Price. In
addition, prior to the Closing Date, each of the Company and the Investor shall
deliver all documents, instruments and writings required to be delivered or
reasonably requested by either of them pursuant to this Agreement in order to
implement and effect the transactions contemplated herein.

          (b)  Company's Failure to Deliver Shares.  If the Company shall fail
to deliver the shares of Common Stock to the Underwriter by the Settlement Date,
the Underwriter shall send a written notice to the Company advising the Company
that such shares have not been received. If, after such notice, the Company
shall fail to issue the shares of Common Stock by the fifth Business Day after
the Settlement Date for such shares, the Company shall pay damages to the
Investor equal to any actual damages incurred by the Investor because of the
Company's failure to deliver such required shares, including damages resulting
from the Investor's need, as determined by the Investor in its sole discretion,
(A) to "unwind" any and all sales of the Company's Common Stock made by the
Investor and to reimburse any and all purchasers for their completed purchases
of the Company's Common Stock and (B)

                                       2
<PAGE>

to "buy in" shares of Common Stock to the extent necessary to satisfy its
securities delivery requirements. Moreover, if the shares have not been
delivered by such date, the Investor will not be obligated to pay the Company
(unless the Company has already paid the Investor's actual damages, if any,
incurred during such Selling Period) for any shares purchased by the Investor or
that the Investor agreed to purchase or was obligated to purchase during the
remainder of the Selling Period. In addition, if the shares have not been
delivered by the Company by the fifth Business Day after the Settlement Date, at
the Investor's sole option, it may terminate this Agreement.

          2.4  Termination, Suspension and Modification of Investment
Obligation.

          (a)  Blocking Events.  The Investor shall not be obligated to purchase
any shares of Common Stock from the Company when there shall exist any one or
more of the following:

               (i)  the withdrawal or suspension of the effectiveness of a
registration statement (the "Registration Statement") for the registration of
not less than the number of shares of Common Stock equal to Maximum Draw Down
Amount divided by the Floor Price, which Registration Statement shall have been
declared effective by the Securities and Exchange Commission (the "SEC");

               (ii)  the failure of the Common Stock issuable hereunder to be
validly listed on the Principal Market;

               (iii)  the Company's failure to satisfy the requirements of
Section 3.1 or 3.3;

               (iv)  any failure or interruption in the compliance by the
Company with any of the covenants provided in Article VI;

               (v)  any merger or consolidation of the Company with or into, or
a transfer of all or substantially all of the assets of the Company to, another
entity; or

               (vi)  receipt or Deemed Receipt (as provided in Section 3.2) by
the Investor of a Notice of Blocking Period (each of (i), (ii), (iii), (iv), (v)
or (vi), a "Blocking Event").

          (b)  The Company shall be obligated to notify the Investor in writing
using the form attached hereto as Exhibit 3.2 immediately upon the occurrence of
a Blocking Event. The Investor shall be entitled, in its sole discretion, to
waive any Blocking Event in writing.

III.  CONDITIONS PRECEDENT.

          3.1  Conditions Precedent to the Obligation of the Investor to
Purchase Common Stock Pursuant to a Capital Demand Notice.  The obligation of
the Investor to purchase Common Stock and to acquire and pay for Common Stock on
the Closing Date is subject to the satisfaction on the Closing Date (the
"Condition Precedent Date") of the conditions precedent set forth in Section 3.1
of the Underwriting Agreement (other than the conditions set forth in
Subsections 3.1(l) and 3.1(n)), which conditions are incorporated by reference
herein as if fully set forth in this Agreement as of the date hereof and which
cannot be waived without the prior written consent of the Investor; provided,
that (i) if any terms are defined in both the Underwriting Agreement and this
Agreement, the defined terms in this Agreement shall govern, (ii) any reference
to Common Stock to be issued pursuant to the Underwriting Agreement shall hereby
refer to Common Stock issuable pursuant to this Agreement, (iii) any reference
to

                                       3
<PAGE>

the Underwriter shall hereby refer to the Investor, unless the context dictates
otherwise and (iv) any reference to the Underwriting Agreement shall hereby
refer to this Agreement, unless the context dictates otherwise.

          3.2  Occurrence of Material Events.  If the Company's management
determines in its good faith judgment (i) that it is required or advisable to do
so or (ii) that any fact exists or any event has occurred that makes any
statement of a material fact made in the Registration Statement, the prospectus,
any amendment or supplement thereto, or any document incorporated by reference
therein untrue in any material respect, or that requires the making of any
additions to or changes in the Registration Statement or the prospectus, in
order to make the statements therein not misleading in any material respect, the
Company shall notify the Investor using the form attached hereto as Exhibit 3.2
(a "Notice of Blocking Period") that it may not sell the Registrable Securities
pursuant to any Registration Statement or prospectus; provided, that if the
Investor reasonably believes, after consultation with its attorneys and with the
Company and after notice to the Company, that a fact exists or an event has
occurred that makes any statement of a material fact made in the Registration
Statement, the prospectus, any amendment or supplement thereto, or any document
incorporated by reference therein untrue in any material respect, or that
requires the making of any additions to or changes in the Registration Statement
or the prospectus, in order to make the statements therein not misleading in any
material respect, then the Company shall have been deemed to have delivered a
Notice of Blocking Period to the Investor. The Investor agrees that, upon
receipt of a Notice of Blocking Period from the Company of the existence of any
fact of the kind described in the immediately preceding sentence, the Investor
shall not dispose of, sell or offer for sale the Registrable Securities pursuant
to the Registration Statement until such Investor receives (i) copies of the
supplemented or amended prospectus, unless counsel for the Company shall have
determined that such disclosure is not required due to subsequent events, (ii)
notice in writing from the Company that the use of the prospectus may be resumed
and (iii) copies of any additional or supplemental filings that are incorporated
by reference in the Prospectus. If so directed by the Company in connection with
any such notice, the Investor will deliver to the Company (at the Company's
expense) all copies, other than permanent file copies then in such Investor's
possession, of the prospectus covering such Registrable Securities that was
current immediately prior to the time of receipt of such notice.

          3.3  Due Diligence Review.  The Investor shall be entitled to rely on
and have the benefits of the due diligence review conducted by the Underwriter
pursuant to Section 3.2 of the Underwriting Agreement.

IV.  REPRESENTATIONS AND WARRANTIES OF INVESTOR.

          The Investor represents and warrants to the Company as follows:

          4.1  Authorization; Enforcement.  The Investor has full power and
authority to execute and deliver this Agreement, and to consummate the
transactions contemplated hereby in accordance with the terms hereof. The
execution and delivery of this Agreement and the consummation of the
transactions contemplated hereby have been duly authorized by the Investor. No
other proceedings on the part of Investor are necessary to approve and authorize
the execution and delivery of this Agreement and the consummation of the
transactions contemplated hereby in accordance with the terms hereof. This
Agreement has been validly executed and delivered by the Investor and is a valid
and binding agreement of the Investor enforceable against it in accordance with
its terms, subject as to enforceability to general principles of equity and to
applicable bankruptcy, insolvency, reorganization, moratorium, liquidation and
similar laws relating to, or affecting generally the enforcement of, applicable
creditors' rights and remedies.

                                       4
<PAGE>

          4.2  Not an Affiliate.  The Investor is not an officer, director or
Affiliate of the Company.

          4.3  Organization and Standing.  The Investor is duly organized,
validly existing, and in good standing under the laws of Delaware, and has all
requisite power and authority to carry on its business as now being conducted,
and is duly qualified to do business and in good standing in each jurisdiction
in which the nature of the business conducted by it makes such qualifications
necessary, except where the failure to be so qualified or in good standing would
not have a material adverse effect.

          4.4  Absence of Conflicts.  The execution and delivery of this
Agreement and any other document or instrument executed in connection herewith,
and the consummation of the transactions contemplated hereby and thereby, and
compliance with the requirements hereof and thereof, will not violate the
provision of any indenture, instrument or agreement to which the Investor is a
party or is subject, or by which the Investor or any of its assets is bound, or
conflict with or constitute a material default thereunder, or result in the
creation or imposition of any lien pursuant to the terms of any such indenture,
instrument or agreement, or constitute a breach of any fiduciary duty owed by
the Investor to any third party.

V.  REPRESENTATIONS AND WARRANTIES OF THE COMPANY.

          5.1  Representations and Warranties Incorporated By Reference.  The
representations and warranties of the Company set forth in Article V of the
Underwriting Agreement are incorporated by reference herein as if fully set
forth in this Agreement as of the date hereof and are for the benefit of the
Investor; provided, that (i) if any terms are defined in both the Underwriting
Agreement and this Agreement, the defined terms in this Agreement shall govern,
(ii) any reference to Common Stock to be issued pursuant to the Underwriting
Agreement shall hereby refer to Common Stock issuable pursuant to this
Agreement, (iii) any reference to the Underwriter shall hereby refer to the
Investor, unless the context dictates otherwise and (iv) any reference to the
Underwriting Agreement shall hereby refer to this Agreement, unless the context
dictates otherwise.

VI.  COVENANTS.

          6.1  Covenants Incorporated By Reference.  In addition to the covenant
set forth below, the covenants set forth in Article VI of the Underwriting
Agreement are incorporated by reference herein as if fully set forth in this
Agreement as of the date hereof and are for the benefit of the Investor;
provided, that (i) if any terms are defined in both the Underwriting Agreement
and this Agreement, the defined terms in this Agreement shall govern, (ii) any
reference to Common Stock to be issued pursuant to the Underwriting Agreement
shall hereby refer to Common Stock issuable pursuant to this Agreement, (iii)
any reference to the Underwriter shall hereby refer to the Investor, unless the
context dictates otherwise and (iv) any reference to the Underwriting Agreement
shall hereby refer to this Agreement, unless the context dictates otherwise.

          6.2  Short Selling.  Investor and its Affiliates shall not engage in
any short selling activities with respect to the Company's Common Stock.

VII.  ASSIGNMENT, ENTIRE AGREEMENT, AMENDMENT, TERMINATION.

          7.1  Successors and Assigns.  Neither this Agreement nor any rights of
the Investor or the Company hereunder may be assigned by either party to any
other Person. Notwithstanding the foregoing, the Investor's rights and
obligations under this Agreement may be assigned at any time, in

                                       5
<PAGE>

whole, with the prior written consent of the Company (which consent shall not be
unreasonably withheld) to any Affiliate of the Investor (a "Permitted
Transferee"). The rights and obligations of the Investor under this Agreement
shall inure to the benefit of, and be enforceable by and against, any such
Permitted Transferee.

          7.2  Entire Agreement; Amendment.  This Agreement, the Underwriting
Agreement and the other documents delivered pursuant hereto constitute the full
and entire understanding and agreement between the parties with regard to the
subjects hereof and thereof, and supercedes all other prior oral or written
agreements between the parties, their Affiliates, or persons acting on their
behalf. No party shall be liable or bound to any other party in any manner by
any warranties, representations or covenants except as specifically set forth in
this Agreement or therein. Except as expressly provided in this Agreement,
neither this Agreement nor any term hereof may be amended, waived, discharged or
terminated other than by a written instrument signed by the party against whom
enforcement of any such amendment, waiver, discharge or termination is sought.

          7.3  Publicity.  Each of the Company and the Investor agrees that they
will not make any disclosure to any Person, issue any press release or make any
other public announcement with respect to the terms hereof and the transactions
contemplated hereby without the prior consent of the other party, unless such
disclosure is required by law or applicable regulation or the listing
requirements of the Principal Market, and then only to the extent of such
requirement; provided, however, neither party may make any disclosure pursuant
to the listing requirements of the Principal Market without prior consultation
with the other party about its contents. Except as may be required by law or
applicable regulation, each of the Company and the Investor shall consult with
the other before issuing any press release or otherwise making any public
statements with respect to this Agreement and, except as required by law,
applicable regulation or the listing requirements of the Principal Market, shall
not issue any such press release or make any such public statement without the
prior written consent of the other party (which consent shall not be
unreasonably withheld).

          7.4  Termination.

          (a)  The Company may, in its sole discretion, terminate the Investor's
obligation to purchase any Common Stock pursuant to Section 2.1; provided,
however, that such termination shall not effect the survival of (i)
representations and warranties pursuant to Articles IV and V, and
indemnification and contribution rights pursuant to Article IX, each as set
forth in Section 10.5, (ii) obligations relating to costs and expenses pursuant
to Section 8.2, (iv) obligations pursuant to Article II, to the extent such
termination shall occur at any time from the beginning of a Selling Period to
the Settlement Date, (v) covenants pursuant to Article VI (other than Section
6.11), to the extent any shares of Common Stock purchased by the Investor
pursuant to this Agreement are held by the Investor, (vi) the provisions of
Articles VII and X, or (vii) any other provisions of this Agreement that may be
reasonably construed to survive the termination of this Agreement.

          (b)  The Investor may (in its sole and absolute discretion) terminate
this Agreement and its obligation to purchase shares of Common Stock as a result
of (i) a material breach by the Company of any material representation,
warranty, covenant or other obligation in connection with this Agreement
(without taking into account materiality qualifications therein), (ii) failure
by the Company to comply with the requirements of Section 6.2, 6.3, 6.4, 6.5 or
6.6 of the Underwriting Agreement (as the terms of such Sections are adjusted
pursuant to the provisos at the end of the first paragraph of Article VI of this
Agreement), (iii) the Company, at any date after the date hereof, effecting any
merger or consolidation of the Company with or into, or transferring all or
substantially all of the assets of the Company to, another entity or (iv) the
Investor reasonably determining, at any time that the adoption of,

                                       6
<PAGE>

or change in, or any change in the interpretation or application of, any law,
regulation, rule, guideline or treaty (including, but not limited to, laws,
regulations, rules or guidelines with respect to changes of capital adequacy)
makes it illegal or materially impracticable for the Investor to fulfill its
commitment pursuant to this Agreement, but in the case of (i) or (iv) above, the
Investor may terminate this Agreement only after a 30-day period beginning when
the Investor gives the Company notice of its intentions to terminate this
Agreement (but the Investor's right to terminate its obligation to purchase any
shares of Common Stock pursuant to a Capital Demand Notice shall not be subject
to any delay or contingency), in which, in the case of (i), the Company has not
cured such breach as provided above, or, in the case of (iv), the parties
negotiate in good faith a reasonable alternative manner not illegal or
impracticable for the Investor to fulfill its commitment pursuant to this
Agreement; provided, however, that such termination shall not effect the
survival of (i) representations and warranties pursuant to Articles IV and V,
and indemnification and contribution rights pursuant to Article IX, each as set
forth in Section 10.5, (ii) obligations relating to costs and expenses pursuant
to Section 8.2, (iv) obligations pursuant to Article II, to the extent such
termination shall occur at any time from the beginning of a Selling Period to
the Settlement Date, (v) covenants pursuant to Article VI (other than Section
6.11), to the extent any shares of Common Stock purchased by the Investor
pursuant to this Agreement are held by the Investor, (vi) the provisions of
Articles VII and X, or (vii) any other provisions of this Agreement that may be
reasonably construed to survive the termination of this Agreement. If the
Company shall fail to comply with the requirements under Section 6.2, 6.3, 6.4,
6.5 or 6.6 of the Underwriting Agreement (as the terms of such Sections are
adjusted pursuant to the provisos at the end of the first paragraph of Article
VI of this Agreement) pursuant to clause (ii) above, the Company shall notify
the Investor within two (2) days of the time it becomes aware of the failure to
comply with any such covenants. If the Investor elects to terminate this
Agreement pursuant to clause (ii) above, it must first give the Company notice
of such election and may terminate this Agreement only after a 10-day period in
which the Company has not cured the failure to materially comply with any such
covenants; provided, however, that such termination shall not effect the
survival of (i) representations and warranties pursuant to Articles IV and V,
and indemnification and contribution rights pursuant to Article IX, each as set
forth in Section 10.5, (ii) obligations relating to costs and expenses pursuant
to Section 8.2, (iv) obligations pursuant to Article II, to the extent such
termination shall occur at any time from the beginning of a Selling Period to
the Settlement Date, (v) covenants pursuant to Article VI , to the extent any
shares of Common Stock purchased by the Investor pursuant to this Agreement are
held by the Investor, (vi) the provisions of Articles VII and X, or (vii) any
other provisions of this Agreement that may be reasonably construed to survive
the termination of this Agreement. The Investor may also, in its sole and
absolute discretion, terminate this Agreement if the Company shall fail to
maintain the listing of the Common Stock on a Principal Market, or if trading of
the Common Stock on a Principal Market shall have been suspended for a period of
ten (10) consecutive Trading Days; provided, however, that such termination
shall not effect the survival of (i) representations and warranties pursuant to
Articles IV and V, and indemnification and contribution rights pursuant to
Article IX, each as set forth in Section 10.5, (ii) obligations relating to
costs and expenses pursuant to Section 8.2, (iv) obligations pursuant to Article
II, to the extent such termination shall occur at any time from the beginning of
a Selling Period to the Settlement Date, (v) covenants pursuant to Article VI
(other than Section 6.11), to the extent any shares of Common Stock purchased by
the Investor pursuant to this Agreement are held by the Investor, (vi) the
provisions of Articles VII and X, or (vii) any other provisions of this
Agreement that may be reasonably construed to survive the termination of this
Agreement. The Investor may waive, in its sole and absolute discretion, in whole
or in part, any of the termination events contained in this Section 7.4.

          (c)  Upon the termination of the Underwriting Agreement pursuant to
Section 7.4 contained therein, this Agreement shall terminate; provided,
however, that such termination shall not affect the continuing obligations of
the parties hereto, as set forth in this Agreement, including the survival of
representations, warranties, covenants and indemnification rights of the
Investor.

                                       7
<PAGE>

VIII.  NOTICES; COSTS AND EXPENSES.

          8.1  Notices.  All notices, demands, requests, consents, approvals or
other communications required or permitted to be given hereunder or which are
given with respect to this Agreement shall be in writing and shall be (i)
personally served, (ii) deposited in the mail, registered or certified, return
receipt requested, postage prepaid, (iii) delivered by reputable air courier
service with charges prepaid, (iv) transmitted by hand delivery, or (v)
transmitted by facsimile, addressed as set forth below, or to such other address
as such party shall have specified most recently by written notice:

          If to the Company, to:

          Onyx Software Corporation
          3180-139th Avenue, Suite 500
          Bellevue, Washington 98005
          Attention:  General Counsel
          Facsimile No.:  (425) 990-3343

          With a copy (which shall not constitute notice) to:

          Orrick Herrington & Sutcliffe, LLP
          701 Fifth Avenue
          Suite 6500
          Seattle, Washington  98104
          Attention:  Stephen M. Graham, Esq.
                      Alan C. Smith, Esq.
          Facsimile No.:  (206) 839-4301

          If to the Investor, to

          Ramius Capital Group, LLC
          666 Third Avenue, 26th Floor
          New York, NY  10017
          Attention:  Jeffrey M. Solomon
          Facsimile No.:  (212) 845-7999

          With a copy (which shall not constitute notice) to:

          Schulte Roth & Zabel LLP
          900 Third Avenue
          New York, NY  10022
          Attention:  Eleazer N. Klein, Esq.
          Facsimile No.:  (212) 593-5955

          Any notice sent by one party to another with confirmation of
acceptance or otherwise received in writing via courier, hand delivery or first-
class mail (return receipt requested) by the Company, or, if received on any day
which is not a Trading Day or after 12:00 noon on a Trading Day, shall be deemed
to be delivered on the immediately succeeding Trading Day. Notice shall be
deemed given on the date of service or transmission if personally served or
transmitted by facsimile during normal business hours of the recipient;
provided, that such transmission by facsimile shall have been confirmed
received. Notice otherwise sent as provided herein shall be deemed given on the
third (3rd) business day

                                       8
<PAGE>

following the date mailed or on the second business day following the date of
deposit for delivery of such notice with a reputable air courier service.

          8.2  Costs and Expenses.  In the event payment from the Company to the
Underwriter is not received within the thirty (30) day period set forth in
Section 8.2 of the Underwriting Agreement, Investor shall have the right to
deduct any such amounts owed by the Company to the Investor or the Underwriter
from any amounts owed by the Investor to the Company pursuant hereto; provided,
however, that Investor shall not exercise such right until the Underwriter
acknowledges, in writing, to the Company, the discharge of the Company's
obligation to the Underwriter pursuant to such right of deduction by the
Investor.

IX.  INDEMNIFICATION AND CONTRIBUTION.

          9.1  Indemnification.

          (a)  To the fullest extent permitted by law, the Company will, and
hereby does, indemnify, hold harmless and defend the Investor, the directors,
officers, partners, employees and agents of the Investor and each Person, if
any, who controls any Investor within the meaning of the Securities Act or the
Exchange Act (each, an "Indemnified Person"), against any losses, claims,
damages, liabilities, judgments, fines, penalties, charges, costs, attorneys'
fees, amounts paid in settlement or expenses, joint or several (collectively,
"Claims"), incurred in investigating, preparing or defending any action, claim,
suit, inquiry, proceeding, investigation or appeal taken from the foregoing by
or before any court or governmental, administrative or other regulatory agency,
body or the SEC or NASD, whether pending or threatened, whether or not such
Indemnified Person is or may be a party thereto ("Indemnified Damages"), to
which any of them may become subject insofar as such Claims (or actions or
proceedings, whether commenced or threatened, in respect thereof) arise out of
or are based upon: (i) any untrue statement or alleged untrue statement of a
material fact in a Registration Statement or any post-effective amendment
thereto or in any filing made in connection with the qualification of the
offering under the securities or other Blue Sky Laws of any jurisdiction in
which Registrable Securities are offered, or the omission or alleged omission to
state a material fact required to be stated therein or necessary to make the
statements therein, in light of the circumstances under which the statements
therein were made, not misleading, (ii) any untrue statement or alleged untrue
statement of a material fact contained in any preliminary prospectus if used
prior to the effective date of such Registration Statement, or contained in the
final prospectus (as amended or supplemented, if the Company files any amendment
thereof or supplement thereto with the SEC) or the omission or alleged omission
to state therein any material fact necessary to make the statements made
therein, in light of the circumstances under which the statements therein were
made, not misleading, (iii) any violation or alleged violation by the Company of
the Securities Act, the Exchange Act, any other law, including, without
limitation, any state securities law, or any rule or regulation thereunder
relating to the offer or sale of the Registrable Securities pursuant to a
Registration Statement, or (iv) any breach of any representation, warranty,
covenant or agreement contained in this Agreement or any document delivered in
connection with this Agreement (the matters in the foregoing clauses (i) through
(iv) being, collectively, "Violations"). The Company shall reimburse the
Investors and each such controlling person, promptly as such expenses are
incurred and are due and payable, for any legal fees or other reasonable
expenses incurred by them in connection with investigating or defending any such
Claim. Notwithstanding anything to the contrary contained herein, the
indemnification agreement contained in this Section 9.1(a): (i) shall not apply
to a Claim arising out of or based upon a Violation which occurs in reliance
upon and in conformity with information furnished in writing to the Company by
any Indemnified Person expressly for use in connection with the preparation of
the Registration Statement or any such amendment thereof or supplement thereto,
if such prospectus was timely made available by the Company; (ii) with respect
to any preliminary prospectus, shall not

                                       9
<PAGE>

inure to the benefit of any such person from whom the person asserting any such
Claim purchased the Registrable Securities that are the subject thereof (or to
the benefit of any person controlling such person) if the untrue statement or
omission of material fact contained in the preliminary prospectus was corrected
in the prospectus, as then amended or supplemented, if such prospectus was
timely made available by the Company, and the Indemnified Person was promptly
advised in writing not to use the incorrect prospectus prior to the use giving
rise to a Violation and such Indemnified Person, notwithstanding such advice,
used it; and (iii) shall not apply to amounts paid in settlement of any Claim if
such settlement is effected without the prior written consent of the Company,
which consent shall not be unreasonably withheld. Such indemnity shall remain in
full force and effect regardless of any investigation made by or on behalf of
the Indemnified Person and shall survive the transfer of the Registrable
Securities by the Investor.

          (b)  In connection with any Registration Statement or any amendment or
supplement thereto in which the Investor is participating, the Investor agrees
to indemnify, hold harmless and defend, to the same extent and in the same
manner as is set forth in Section 9.1(a), the Company, each of its directors,
each of its officers who signs the Registration Statement, each Person, if any,
who controls the Company within the meaning of the Securities Act or the
Exchange Act (each, an "Indemnified Party"), against any Claim or Indemnified
Damages to which any of them may become subject, under the Securities Act, the
Exchange Act or otherwise, insofar as such Claim or Indemnified Damages arise
out of or are based upon (i) any Violation, in each case to the extent, and only
to the extent, that such Violation occurs in reliance upon and in conformity
with written information furnished to the Company by such Investor expressly for
use in connection with any Registration Statement covering Registrable
Securities or (ii) the purchase or sale of Common Stock by the Underwriter
pursuant to the Registration Statement despite the fact that the Investor has
received a Notice of Blocking Period from the Company and has not received
notice from the Company signaling the end of such Blocking Period; and, subject
to Section 9.1(c), such Investor will reimburse such Indemnified Parties
promptly as such expenses are incurred and are due and payable for any legal or
other expenses reasonably incurred by them in connection with investigating or
defending any such Claim; provided, however, that the indemnity agreement
contained in this Section 9.1(b) and the agreement with respect to contribution
contained in Section 9.2 shall not apply to amounts paid in settlement of any
Claim if such settlement is effected without the prior written consent of such
Investor, which consent shall not be unreasonably withheld; provided, further,
however, that the Investor shall be liable under this Section 9.1(b) for only
that amount of a Claim or Indemnified Damages as does not exceed the net
proceeds to such Investor as a result of the sale of Registrable Securities
pursuant to such Registration Statement. Such indemnity shall remain in full
force and effect regardless of any investigation made by or on behalf of such
Indemnified Party and shall survive the transfer of the Registrable Securities
by the Investor. Notwithstanding anything to the contrary contained herein, the
indemnification agreement contained in this Section 9.1(b) with respect to any
preliminary prospectus shall not inure to the benefit of any Indemnified Party
if the untrue statement or omission of material fact contained in the
preliminary prospectus was corrected on a timely basis in the prospectus, as
then amended or supplemented.

          (c)  Promptly after receipt by an Indemnified Person or Indemnified
Party under this Section 9.1 of notice of the commencement of any action or
proceeding (including any governmental action or proceeding) involving a Claim,
such Indemnified Person or Indemnified Party shall, if a Claim in respect
thereof is to be made against any indemnifying party under this Section 9.1,
deliver to the indemnifying party a written notice of the commencement thereof,
and the indemnifying party shall have the right (at its expense) to participate
in, and, to the extent the indemnifying party so desires, jointly with any other
indemnifying party similarly noticed, to assume control of the defense thereof
with counsel mutually satisfactory to the indemnifying party and the Indemnified
Person or the Indemnified Party, as the case may be; provided, however, that
such indemnifying party shall diligently pursue such defense

                                       10
<PAGE>

and that an Indemnified Person or Indemnified Party shall have the right to
retain its own counsel with the fees and expenses to be paid by the indemnifying
party, if, in the reasonable opinion of counsel retained by the Indemnified
Person or Indemnified Party, as the case may be, the representation by such
counsel of the Indemnified Person or Indemnified Party and the indemnifying
party would be inappropriate due to actual or potential differing interests
between such Indemnified Person or Indemnified Party and any other party
represented by such counsel in such proceeding. The indemnifying party shall pay
reasonable fees for only one separate legal counsel for all Indemnified Persons
or Indemnified Parties (as applicable). The Indemnified Party or Indemnified
Person shall cooperate fully with the indemnifying party in connection with any
negotiation or defense of any such action or claim by the indemnifying party and
shall furnish to the indemnifying party all information reasonably available to
the Indemnified Party or Indemnified Person which relates to such action or
claim. The indemnifying party shall keep the Indemnified Party or Indemnified
Person fully apprised at all times as to the status of the defense or any
settlement negotiations with respect thereto. No indemnifying party shall be
liable for any settlement of any action, claim or proceeding effected without
its written consent, provided, however, that the indemnifying party shall not
unreasonably withhold, delay or condition its consent. No indemnifying party
shall, without the consent of the Indemnified Party or Indemnified Person,
consent to entry of any judgment or enter into any settlement or other
compromise which does not include as an unconditional term thereof the giving by
the claimant or plaintiff to such Indemnified Party or Indemnified Person of a
release from all liability in respect to such claim or litigation. Following
indemnification as provided for hereunder, the indemnifying party shall be
subrogated to all rights of the Indemnified Party or Indemnified Person with
respect to all third parties, firms or corporations relating to the matter for
which indemnification has been made. The failure to deliver written notice to
the indemnifying party within a reasonable time of the commencement of any such
action shall not relieve such indemnifying party of any liability to the
Indemnified Person or Indemnified Party under this Section 9.1, except to the
extent that the indemnifying party is prejudiced in its ability to defend such
action.

          (d)  The indemnification required by this Section 9.1 shall be made by
periodic payments of the amount thereof during the course of the investigation
or defense, as and when bills are received or Indemnified Damages are incurred.

          (e)  The indemnity agreements contained herein shall be in addition to
(i) any cause of action or similar right of the Indemnified Party or Indemnified
Person against the indemnifying party or others, and (ii) any liabilities the
indemnifying party may be subject to pursuant to the law.

          9.2  Contribution.  To the extent any indemnification by an
indemnifying party is prohibited or limited by law, the indemnifying party
agrees to make the maximum contribution with respect to any amounts for which it
would otherwise be liable under Section 9.1 to the fullest extent permitted by
law; provided, however, that: (i) no contribution shall be made under
circumstances where the maker would not have been liable for indemnification
under the fault standards set forth in Section 9.1; (ii) no seller of
Registrable Securities guilty of fraudulent misrepresentation (within the
meaning of Section 10(f) of the Securities Act) shall be entitled to
contribution from any seller of Registrable Securities who was not guilty of
fraudulent misrepresentation; and (iii) contribution by any seller of
Registrable Securities shall be limited in amount to the net amount of proceeds
received by such seller from the sale of such Registrable Securities.

X.  GOVERNING LAW; MISCELLANEOUS.

          10.1  Governing Law.  This Agreement shall be governed by and
interpreted in accordance with the laws of the State of New York without regard
to the principles of conflict of laws.

                                       11
<PAGE>

          10.2  Counterparts.  This Agreement may be executed in any number of
counterparts, all of which shall be considered one and the same agreement and
shall become effective when counterparts have been signed by each party and
delivered to the other party. In the event any signature page is delivered by
facsimile transmission, the party using such means of delivery shall cause four
(4) additional original executed signature pages to be physically delivered to
the other party within five (5) days of the execution and delivery hereof.

          10.3  Headings.  The headings of this Agreement are for convenience of
reference and shall not form part of, or affect the interpretation of, this
Agreement.

          10.4  Severability.  If any provision of this Agreement shall be
invalid or unenforceable in any jurisdiction, such invalidity or
unenforceability shall not affect the validity or enforceability of the
remainder of this Agreement in that jurisdiction or the validity or
enforceability of any provision of this Agreement in any other jurisdiction;
provided that such severability shall be ineffective if it materially changes
the economic benefit of this Agreement to any party.

          10.5  Survival.  The representations, warranties, and agreements of
the parties hereto shall survive each Closing hereunder and the termination of
this Agreement or the Commitment Period. The indemnity and contribution
agreements contained in Sections 9.1 and 9.2 hereof shall survive and remain
operative and in full force and effect regardless of (i) any termination of this
Agreement, (ii) any investigation made by or on behalf of any indemnified party
or by or on behalf of the Company, and (iii) the consummation of the sale or
successive resales of the Common Stock.

          10.6  No Third Party Beneficiaries.  This Agreement is intended for
the benefit of the parties hereto and their respective permitted successors and
assigns, and is not for the benefit of, nor may any provision hereof be enforced
by, any other person, except as provided in Article IX.

          10.7  Further Assurances.  Each party shall do and perform, or cause
to be done and performed, all such further acts and things, and shall execute
and deliver all such other agreements, certificates, instruments and documents,
as the other party may reasonably request in order to carry out the intent and
accomplish the purposes of this Agreement and the consummation of the
transactions contemplated hereby.

          10.8  Construction.  The language used in this Agreement will be
deemed to be the language chosen by the parties to express their mutual intent,
and no rules of strict construction will be applied against any party. Unless
the context of this Agreement otherwise clearly requires, references to the
plural include the singular, the singular the plural and the part the whole and
"or" has the inclusive meaning represented by the phrase "and/or". Unless the
context requires otherwise, (i) any definition of or reference to any agreement,
instrument or other document herein shall be construed as referring to such
agreement, instrument or other document as from time to time amended,
supplemented or otherwise modified (subject to any restrictions on such
amendments, supplements or modifications set forth herein), (ii) any reference
herein to any Person shall be construed to include such Person's successors and
assigns, (iii) the words "herein", "hereof" and "hereunder", and words of
similar import, shall be construed to refer to this Agreement in its entirety
and not to any particular provision hereof, and (iv) all references herein to
Articles, Sections, Exhibits and Schedules shall be construed to refer to
Articles and Sections of, and Exhibits and Schedules to, this Agreement.

          10.9  Equitable Relief.  The Company recognizes that in the event that
it fails to perform, observe, or discharge any or all of its obligations under
this Agreement, any remedy at law may prove to be inadequate relief to the
Investor. The Company therefore agrees that the Investor shall be

                                       12
<PAGE>

entitled to seek temporary and permanent injunctive relief in any such case
without the necessity of proving actual damages.

          10.10  Consent to Jurisdiction.  The parties hereto expressly submit
themselves to the exclusive jurisdiction of the state and federal courts of New
York, New York in any action or proceeding relating to this Agreement or any of
the other documents contemplated hereby or any of the transactions contemplated
hereby or thereby. Each party hereby irrevocably waives, to the fullest extent
permitted by law, any objection that it may now or hereafter have to the laying
of venue of any such action, suit or proceeding brought in such a court and any
claim that any such action, suit or proceeding brought in such a court has been
brought in an inconvenient forum. The parties hereto hereby irrevocably waive
any and all right to a trial by jury with respect to any legal proceeding
arising out of or relating to this Agreement or the transactions contemplated
hereby. The parties hereto irrevocably and unconditionally consent to the
service of process of any of the aforementioned courts in any such action, suit
or proceeding by the mailing of copies thereof by registered or certified mail,
return receipt requested, postage prepaid, at their respective addresses set
forth or provided for herein, such service to become effective ten (10) days
after such mailing. Nothing herein shall affect the right of any party to serve
process in any manner permitted by law or to commence legal proceedings or
otherwise proceed against the other parties in any other jurisdiction.

                                       13
<PAGE>

          IN WITNESS WHEREOF, the parties hereto have caused this Agreement to
be duly executed by their respective authorized officers as of the date hereof.

                                         RAMIUS CAPITAL GROUP, LLC

                                         By: /s/ Peter Cohen
                                            -----------------------------
                                                  Name: Peter Cohen
                                                  Title: Principal

                                         ONYX SOFTWARE CORPORATION

                                         By: /s/ Amy E. Kelleran
                                            -----------------------------
                                                  Name: Amy E. Kelleran
                                                  Title: Interim CFO





                            EXECUTION COPY STAND-BY
                              PURCHASE AGREEMENT