<PAGE>

                                                                     Exhibit 4.5
                                                               EXECUTION VERSION

THESE SECURITIES HAVE NOT BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE
COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN
EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE
"SECURITIES ACT"), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT
TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR PURSUANT TO
AN AVAILABLE EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT
AND IN COMPLIANCE WITH APPLICABLE STATE SECURITIES OR BLUE SKY LAWS. THESE
SECURITIES AND THE SECURITIES ISSUABLE UPON EXERCISE OF THESE SECURITIES MAY BE
PLEDGED IN CONNECTION WITH A BONA FIDE MARGIN ACCOUNT OR OTHER LOAN SECURED BY
SUCH SECURITIES.


                            MERCATOR SOFTWARE, INC.

                                    WARRANT
                                    -------

Warrant No. [_]                                         Dated: December 11, 2001

     Mercator Software, Inc., a Delaware corporation (the "Company"), hereby
certifies that, for value received, [Name of Holder] or its registered assigns
(the "Holder"), is entitled to purchase from the Company up to a total of [ ]
shares of common stock, $0.01 par value per share (the "Common Stock"), of the
Company (each such share, a "Warrant Share" and all such shares, the "Warrant
Shares") at an exercise price equal to $8.98 per share (as adjusted from time to
time as provided in Section 8, the "Exercise Price"), at any time and from time
                    ---------
to time from and after the date hereof and through and including December 11,
2008 (the "Expiration Date"), and subject to the following terms and conditions.
This Warrant (this "Warrant") is one of a series of similar warrants issued
pursuant to that certain Securities Purchase Agreement, dated as of the date
hereof, by and among the Company and the Purchasers identified therein (the
"Purchase Agreement"). All such warrants are referred to herein, collectively,
as the "Warrants."

     1.   Definitions.  In addition to the terms defined elsewhere in this
          -----------
Warrant, capitalized terms that are not otherwise defined herein have the
meanings given to such terms in the Purchase Agreement.

     2.   Registration of Warrant.  The Company shall register this Warrant,
          -----------------------
upon records to be maintained by the Company for that purpose (the "Warrant
Register"), in the name of the record Holder hereof from time to time. The
Company may deem and treat the registered Holder of this Warrant as the absolute
owner hereof for the purpose of any exercise hereof or any distribution to the
Holder, and for all other purposes, absent actual notice to the contrary.

     3.   Registration of Transfers.  The Company shall register the transfer of
          -------------------------
any portion of this Warrant in the Warrant Register, upon surrender of this
Warrant, with the Form of
<PAGE>

Assignment attached hereto duly completed and signed, to the Transfer Agent or
to the Company at its address specified herein. Upon any such registration or
transfer, a new warrant to purchase Common Stock, in substantially the form of
this Warrant (any such new warrant, a "New Warrant"), evidencing the portion of
this Warrant so transferred shall be issued to the transferee and a New Warrant
evidencing the remaining portion of this Warrant not so transferred, if any,
shall be issued to the transferring Holder. The acceptance of the New Warrant by
the transferee thereof shall be deemed the acceptance by such transferee of all
of the rights and obligations of a holder of a Warrant.

     4.   Exercise and Duration of Warrant.
          --------------------------------

          (a)  This Warrant shall be exercisable by the registered Holder at any
time and from time to time on or after the date hereof to and including the
Expiration Date. At 6:30 P.M., New York City time on the Expiration Date, the
portion of this Warrant not exercised prior thereto shall be and become void and
of no value; provided that, if the average of the Closing Prices for the five
Trading Days immediately prior to (but not including) the Expiration Date
exceeds the Exercise Price on the Expiration Date, then this Warrant shall be
deemed to have been exercised in full (to the extent not previously exercised)
on a "cashless exercise" basis at 6:30 P.M. New York City time on the Expiration
Date.

          (b)  A Holder may exercise this Warrant by delivering to the Company
(i) an Exercise Notice, in the form attached hereto, appropriately completed and
duly signed, and (ii) payment of the Exercise Price for the number of Warrant
Shares as to which this Warrant is being exercised (which may take the form of a
"cashless exercise" if so indicated in the Exercise Notice), and the date such
items are delivered to the Company (as determined in accordance with the notice
provisions hereof) is an "Exercise Date." The Holder shall not be required to
deliver the original Warrant in order to effect an exercise hereunder. Execution
and delivery of the Exercise Notice shall have the same effect as cancellation
of the original Warrant and issuance of a New Warrant evidencing the right to
purchase the remaining number of Warrant Shares.

     5.   Delivery of Warrant Shares.
          --------------------------

          (a)  Upon exercise of this Warrant, the Company shall promptly (but in
no event later than three Trading Days after the Exercise Date) issue or cause
to be issued and cause to be delivered to or upon the written order of the
Holder and in such name or names as the Holder may designate, a certificate for
the Warrant Shares issuable upon such exercise, free of restrictive legends
unless a registration statement covering the resale of the Warrant Shares and
naming the Holder as a selling stockholder thereunder is not then effective and
the Warrant Shares are not freely transferable without volume restrictions
pursuant to Rule 144 under the Securities Act. The Holder, or any Person so
designated by the Holder to receive Warrant Shares, shall be deemed to have
become holder of record of such Warrant Shares as of the Exercise Date. The
Company shall, upon request of the Holder, use its commercially reasonable best
efforts to deliver Warrant Shares hereunder electronically through the
Depository Trust Corporation or another established clearing corporation
performing similar functions.

          (b)  This Warrant is exercisable, either in its entirety or, from time
to time, for a portion of the number of Warrant Shares. Upon surrender of this
Warrant following one or
<PAGE>

more partial exercises, the Company shall issue or cause to be issued, at its
expense, a New Warrant evidencing the right to purchase the remaining number of
Warrant Shares.

          (c)  The Company's obligations to issue and deliver Warrant Shares in
accordance with the terms hereof are absolute and unconditional, irrespective of
any action or inaction by the Holder to enforce the same, any waiver or consent
with respect to any provision hereof, the recovery of any judgment against any
Person or any action to enforce the same, or any setoff, counterclaim,
recoupment, limitation or termination, or any breach or alleged breach by the
Holder or any other Person of any obligation to the Company or any violation or
alleged violation of law by the Holder or any other Person, and irrespective of
any other circumstance which might otherwise limit such obligation of the
Company to the Holder in connection with the issuance of Warrant Shares.

     6.   Charges, Taxes and Expenses.   Issuance of certificates for shares of
          ---------------------------
Common Stock upon exercise of this Warrant shall be made without charge to the
Holder for any issue or transfer tax, withholding tax, transfer agent fee or
other incidental tax or expense in respect of the issuance of such certificates,
all of which taxes and expenses shall be paid by the Company; provided, however,
                                                              --------  -------
that the Company shall not be required to pay any tax which may be payable in
respect of any transfer involved in the registration of any certificates for
Warrant Shares or Warrants in a name other than that of the Holder.  The Holder
shall be responsible for all other tax liability that may arise as a result of
holding or transferring this Warrant or receiving Warrant Shares upon exercise
hereof.

     7.   Reservation of Warrant Shares.  The Company covenants that it will at
          -----------------------------
all times reserve and keep available out of the aggregate of its authorized but
unissued and otherwise unreserved Common Stock, solely for the purpose of
enabling it to issue Warrant Shares upon exercise of this Warrant as herein
provided, the number of Warrant Shares which are then issuable and deliverable
upon the exercise of this entire Warrant, free from preemptive rights or any
other contingent purchase rights of persons other than the Holder (taking into
account the adjustments and restrictions of Section 8). The Company covenants
                                            ---------
that all Warrant Shares so issuable and deliverable shall, upon issuance and the
payment of the applicable Exercise Price in accordance with the terms hereof, be
duly and validly authorized, issued and fully paid and nonassessable.  The
Company will take all such action as may be necessary to assure that such shares
of stock may be issued as provided herein without violation of any applicable
law or regulation, or of any requirements of any securities exchange or
automated quotation system upon which the stock may be listed (it being
understood that the Company shall not be required to take any action to assure
the issuance of stock to any Purchaser to the extent that such issuance is
prohibited by some act or failure to act of such Purchaser).

     8.   Certain Adjustments.  The Exercise Price and number of Warrant Shares
          -------------------
issuable upon exercise of this Warrant are subject to adjustment from time to
time as set forth in this Section 8.
                          ---------

          (a)  Stock Dividends and Splits.  If the Company, at any time while
               --------------------------
this Warrant is outstanding, (i) pays a stock dividend on its Common Stock or
otherwise makes a distribution on any class of capital stock that is payable in
shares of Common Stock, (ii) subdivides outstanding shares of Common Stock into
a larger number of shares, or (iii) combines
<PAGE>

outstanding shares of Common Stock into a smaller number of shares, then in each
such case the Exercise Price shall be multiplied by a fraction of which the
numerator shall be the number of shares of Common Stock outstanding immediately
before such event and of which the denominator shall be the number of shares of
Common Stock outstanding immediately after such event. Any adjustment made
pursuant to clause (i) of this paragraph shall become effective immediately
after the record date for the determination of stockholders entitled to receive
such dividend or distribution, and any adjustment pursuant to clause (ii) or
(iii) of this paragraph shall become effective immediately after the effective
date of such subdivision or combination.

          (b)  Pro Rata Distributions.  If the Company, at any time while this
               ----------------------
Warrant is outstanding, distributes to holders of Common Stock (i) evidences of
its indebtedness, (ii) any security (other than a distribution of Common Stock
covered by the preceding paragraph), (iii) rights or warrants to subscribe for
or purchase any security, or (iv) any other asset (in each case, "Distributed
Property"), then in each such case the Exercise Price in effect immediately
prior to the record date fixed for determination of stockholders entitled to
receive such distribution shall be adjusted (effective on such record date) to
equal the product of such Exercise Price times a fraction of which the
denominator shall be the average of the Closing Prices for the five Trading Days
immediately prior to (but not including) such record date and of which the
numerator shall be such average less the then fair market value of the
Distributed Property distributed in respect of one outstanding share of Common
Stock, as determined by the Company's independent certified public accountants
that regularly examine the financial statements of the Company (an "Appraiser").
In such event, the Holder, after receipt of the determination by the Appraiser,
shall have the right to select an additional appraiser (which shall be a
nationally recognized accounting firm), in which case such fair market value
shall be deemed to equal the average of the values determined by each of the
Appraiser and such appraiser. As an alternative to the foregoing adjustment to
the Exercise Price, at the request of the Holder delivered before the 90th day
after such record date, the Company will hold in escrow (for future delivery to
the Holder only upon exercise of this Warrant, as provided below) the
Distributed Property that such Holder would have been entitled to receive in
respect of the Warrant Shares for which this Warrant could have been exercised
immediately prior to such record date and shall deliver such Distributed
Property to such Holder only upon exercise, if any, of this Warrant.

          (c)  Fundamental Transactions.  If, at any time while this Warrant is
               ------------------------
outstanding, (i) the Company effects any merger or consolidation of the Company
with or into another Person, (ii) the Company effects any sale of all or
substantially all of its assets in one or a series of related transactions,
(iii) any tender offer or exchange offer (whether by the Company or another
Person) is completed pursuant to which holders of Common Stock are permitted to
tender or exchange their shares for other securities, cash or property, or (iv)
the Company effects any reclassification of the Common Stock or any compulsory
share exchange pursuant to which the Common Stock is effectively converted into
or exchanged for other securities, cash or property (in any such case, a
"Fundamental Transaction"), then the Holder shall have the right thereafter to
receive, upon exercise of this Warrant, the same amount and kind of securities,
cash or property as it would have been entitled to receive upon the occurrence
of such Fundamental Transaction if it had been, immediately prior to such
Fundamental Transaction, the holder of the number of Warrant Shares then
issuable upon exercise in full of this Warrant (the "Alternate Consideration").
The aggregate Exercise Price for this Warrant will not be affected by any such
<PAGE>

Fundamental Transaction, but the Company shall apportion such aggregate Exercise
Price among the Alternate Consideration in a reasonable manner reflecting the
relative value of any different components of the Alternate Consideration. If
holders of Common Stock are given any choice as to the securities, cash or
property to be received in a Fundamental Transaction, then the Holder shall be
given the same choice as to the Alternate Consideration it receives upon any
exercise of this Warrant following such Fundamental Transaction. At the Holder's
request, any successor to the Company or surviving entity in such Fundamental
Transaction shall issue to the Holder a new warrant consistent with the
foregoing provisions and evidencing the Holder's right to purchase the Alternate
Consideration for the aggregate Exercise Price upon exercise thereof. The terms
of any agreement pursuant to which a Fundamental Transaction is effected shall
include terms requiring any such successor or surviving entity to comply with
the provisions of this paragraph (c) and insuring that the Warrant (or any such
replacement security) will be similarly adjusted upon any subsequent transaction
analogous to a Fundamental Transaction.

          (d)  Subsequent Equity Sales.
               -----------------------
               (i)  If, at any time while this Warrant is outstanding, the
     Company or any Subsidiary issues additional shares of Common Stock or
     rights, warrants, options or other securities or debt convertible,
     exercisable or exchangeable for shares of Common Stock or otherwise
     entitling any Person to acquire shares of Common Stock (collectively,
     "Common Stock Equivalents") at an effective price (net of any discounts,
     fees, commissions and other expenses that are not customary) to the Company
     per share of Common Stock (the "Effective Price") less than the Exercise
     Price (as adjusted hereunder to such date), then the Exercise Price shall
     be reduced to equal the Effective Price. For purposes of this paragraph, in
     connection with any issuance of any Common Stock Equivalents, (A) the
     maximum number of shares of Common Stock potentially issuable at any time
     upon conversion, exercise or exchange of such Common Stock Equivalents (the
     "Deemed Number") shall be deemed to be outstanding upon issuance of such
     Common Stock Equivalents, (B) the Effective Price applicable to such Common
     Stock shall equal the minimum dollar value of consideration payable to the
     Company to purchase such Common Stock Equivalents and to convert, exercise
     or exchange them into Common Stock (net of any discounts, fees, commissions
     and other expenses that are not customary), divided by the Deemed Number,
     and (C) no further adjustment shall be made to the Exercise Price upon the
     actual issuance of Common Stock upon conversion, exercise or exchange of
     such Common Stock Equivalents.

               (ii) If, at any time while this Warrant is outstanding, the
     Company or any Subsidiary issues Common Stock Equivalents with an Effective
     Price or a number of underlying shares that floats or resets or otherwise
     varies or is subject to adjustment based (directly or indirectly) on market
     prices of the Common Stock (a "Floating Price Security"), then for purposes
     of applying the preceding paragraph in connection with any subsequent
     exercise, the Effective Price will be determined separately on each
     Exercise Date and will be deemed to equal the lowest Effective Price at
     which any holder of such Floating Price Security is entitled to acquire
     Common Stock on such Exercise Date (regardless of whether any such holder
     actually acquires any shares on such date).
<PAGE>

               (iii)  Notwithstanding the foregoing, no adjustment will be made
     under this paragraph (d) in respect of any Excluded Stock.

          (e)  Number of Warrant Shares.  Simultaneously with any adjustment to
               ------------------------
the Exercise Price pursuant to paragraphs (a), (b) or (d) of this Section, the
number of Warrant Shares that may be purchased upon exercise of this Warrant
shall be increased or decreased proportionately, so that after such adjustment
the aggregate Exercise Price payable hereunder for the increased or decreased
number of Warrant Shares shall be the same as the aggregate Exercise Price in
effect immediately prior to such adjustment.

          (f)  Calculations.  All calculations under this Section 8 shall be
               ------------                               ---------
made to the nearest cent or the nearest 1/100th of a share, as applicable. The
number of shares of Common Stock outstanding at any given time shall not include
shares owned or held by or for the account of the Company, and the disposition
of any such shares shall be considered an issue or sale of Common Stock.

          (g)  Notice of Adjustments.  Upon the occurrence of each adjustment
               ---------------------
pursuant to this Section 8, the Company at its expense will promptly compute
                 ---------
such adjustment in accordance with the terms of this Warrant and prepare a
certificate setting forth such adjustment, including a statement of the adjusted
Exercise Price and adjusted number or type of Warrant Shares or other securities
issuable upon exercise of this Warrant (as applicable), describing the
transactions giving rise to such adjustments and showing in detail the facts
upon which such adjustment is based. Upon written request, the Company will
promptly deliver a copy of each such certificate to the Holder and to the
Company's Transfer Agent.

          (h)  Notice of Corporate Events.  If the Company (i) declares a
               --------------------------
dividend or any other distribution of cash, securities or other property in
respect of its Common Stock, including without limitation any granting of rights
or warrants to subscribe for or purchase any capital stock of the Company or any
Subsidiary, (ii) authorizes or approves, enters into any agreement contemplating
or solicits stockholder approval for any Fundamental Transaction or (iii)
authorizes the voluntary dissolution, liquidation or winding up of the affairs
of the Company, then the Company shall deliver to the Holder a notice describing
the material terms and conditions of such transaction, at least 20 calendar days
prior to the applicable record or effective date on which a Person would need to
hold Common Stock in order to participate in or vote with respect to such
transaction, and the Company will take all steps reasonably necessary in order
to insure that the Holder is given the practical opportunity to exercise this
Warrant prior to such time so as to participate in or vote with respect to such
transaction; provided, however, that the failure to deliver such notice or any
defect therein shall not affect the validity of the corporate action required to
be described in such notice.

     9.   Payment of Exercise Price. The Holder shall pay the Exercise Price in
          -------------------------
one of the following manners:

          (a)  Cash Exercise. The Holder may deliver immediately available
               -------------
funds; or

                                       6
<PAGE>

          (b)  Cashless Exercise. The Holder may satisfy its obligation to pay
               -----------------
     the Exercise Price through a "cashless exercise," in which event the
     Company shall issue to the Holder the number of Warrant Shares determined
     as follows:

                    X = Y [(A-B)/A]

          where:
                    X = the number of Warrant Shares to be issued to the Holder.

                    Y = the number of Warrant Shares with respect to which this
                    Warrant is being exercised.

                    A = the average of the Closing Prices for the five Trading
                    Days immediately prior to (but not including) the Exercise
                    Date.

                    B = the Exercise Price.

For purposes of Rule 144 promulgated under the Securities Act, it is intended,
understood and acknowledged that the Warrant Shares issued in a cashless
exercise transaction shall be deemed to have been acquired by the Holder, and
the holding period for the Warrant Shares shall be deemed to have commenced, on
the date this Warrant was originally issued pursuant to the Purchase Agreement.

     10.  Limitation on Exercise.
          ----------------------

          (a)  Notwithstanding anything to the contrary contained herein, the
number of shares of Common Stock that may be acquired by the Holder upon any
exercise of this Warrant (or otherwise in respect hereof) shall be limited to
the extent necessary to insure that, following such exercise (or other
issuance), the total number of shares of Common Stock then beneficially owned by
such Holder and its Affiliates and any other Persons whose beneficial ownership
of Common Stock would be aggregated with the Holder's for purposes of Section
13(d) of the Exchange Act, does not exceed 4.999% (the "Maximum Percentage") of
the total number of issued and outstanding shares of Common Stock (including for
such purpose the shares of Common Stock issuable upon such exercise). For such
purposes, beneficial ownership shall be determined in accordance with Section
13(d) of the Exchange Act and the rules and regulations promulgated thereunder.
Each delivery of an Exercise Notice hereunder will constitute a representation
by the Holder that it has evaluated the limitation set forth in this paragraph
and determined that issuance of the full number of Warrant Shares requested in
such Exercise Notice is permitted under this paragraph. The Company's obligation
to issue shares of Common Stock in excess of the limitation referred to in this
Section shall be suspended (and shall not terminate or expire notwithstanding
any contrary provisions hereof) until such time, if any, as such shares of
Common Stock may be issued in compliance with such limitation; provided,
                                                               --------
however, that no such suspension shall extend the term during which this Warrant
-------
may be exercised beyond the Expiration Date. By written notice to the Company,
the Holder may waive the provisions of this Section or increase or decrease the
Maximum Percentage to any other percentage specified in such notice, but (i) any
such waiver or increase will not be effective until the 61st day after such

                                       7
<PAGE>


notice is delivered to the Company, and (ii) any such waiver or increase or
decrease will apply only to the Holder and not to any other holder of Warrants.

          (b)  Notwithstanding anything to the contrary contained herein, if the
Trading Market is the Nasdaq National Market or the Nasdaq SmallCap Market or
any other market or exchange with similar applicable rules, then the maximum
number of shares of Common Stock that the Company may issue pursuant to the
Transaction Documents at an effective purchase price less than the Closing Price
on the Trading Day immediately preceding the Closing Date equals 6,123,402
shares (the "Issuable Maximum"), unless the Company obtains shareholder approval
in accordance with the rules and regulations of such Trading Market.  If, at the
time any Purchaser requests an exercise of any of the Warrants, the Actual
Minimum (excluding any shares issued or issuable at an effective purchase price
in excess of the Closing Price on the Trading Day immediately preceding the
Closing Date) exceeds the Issuable Maximum (and if the Company has not
previously obtained the required shareholder approval), then the Company shall
issue to the Purchaser requesting such exercise a number of shares of Common
Stock not exceeding such Purchaser's pro-rata portion of the Issuable Maximum
(based on such Purchaser's share (vis-a-vis other Purchasers) of the aggregate
purchase price paid under the Purchase Agreement and taking into account any
Warrant Shares previously issued to such Purchaser), and the remainder of the
Warrant Shares issuable in connection with such exercise or conversion (if any)
shall constitute "Excess Shares" pursuant to Section 10(c) below.

          (c)  In the event that any Purchaser's receipt of shares of Common
Stock upon exercise of this Warrant is restricted based on the Issuable Maximum,
the Company shall either: (i) use its best efforts to obtain the required
shareholder approval necessary to permit the issuance of such Excess Shares as
soon as is reasonably possible, but in any event not later than the 60th day
after the event giving rise to such Excess Shares, or (ii) within five Trading
Days after such event, pay cash to such Purchaser, as liquidated damages and not
as a penalty, in an amount equal to the difference between the Black Scholes
value of this Warrant assuming the limitations in Section 10(b) were not
applicable and the Black Scholes value of this Warrant after giving effect to
the limitations in Section 10(b), measured as of the date of such event or, if
greater, the date of payment (such difference, the "Cash Amount").  If the
Company elects the first option under the preceding sentence and the Company
fails to obtain the required shareholder approval on or prior to the 60th day
after such event, then within three Trading Days after such 60th day, the
Company shall pay the Cash Amount to such Purchaser, as liquidated damages and
not as a penalty.

     11.  Fractional Shares.  The Company shall not be required to issue or
          -----------------
cause to be issued fractional Warrant Shares on the exercise of this Warrant. If
any fraction of a Warrant Share would, except for the provisions of this
Section, be issuable upon exercise of this Warrant, the number of Warrant Shares
to be issued will be rounded down to the nearest whole share and the Company
shall pay to the Holder an amount in cash equal to the fair market value of such
fractional share (as determined in good faith by the Board of Directors of the
Company).

     12.  Notices.  Any and all notices or other communications or deliveries
          -------
hereunder (including without limitation any Exercise Notice) shall be in writing
and shall be deemed given and effective on the earliest of (i) the date of
transmission, if such notice or communication is delivered via facsimile at the
facsimile number specified in this Section prior to 6:30 p.m. (New

                                       8
<PAGE>

York City time) on a Trading Day, (ii) the next Trading Day after the date of
transmission, if such notice or communication is delivered via facsimile at the
facsimile number specified in this Section on a day that is not a Trading Day or
later than 6:30 p.m. (New York City time) on any Trading Day, (iii) the Trading
Day following the date of mailing, if sent by nationally recognized overnight
courier service, or (iv) upon actual receipt by the party to whom such notice is
required to be given. The address for such notices or communications shall be as
set forth in the Purchase Agreement.

     13.  Warrant Agent.  The Company shall serve as warrant agent under this
          -------------

Warrant.  Upon 30 days' notice to the Holder, the Company may appoint a new
warrant agent.  Any corporation into which the Company or any new warrant agent
may be merged or any corporation resulting from any consolidation to which the
Company or any new warrant agent shall be a party or any corporation to which
the Company or any new warrant agent transfers substantially all of its
corporate trust or shareholders services business shall be a successor warrant
agent under this Warrant without any further act.  Any such successor warrant
agent shall promptly cause notice of its succession as warrant agent to be
mailed (by first class mail, postage prepaid) to the Holder at the Holder's last
address as shown on the Warrant Register.

     14.  Miscellaneous.
          -------------

          (a)  This Warrant shall be binding on and inure to the benefit of the
parties hereto and their respective successors and assigns. Subject to the
preceding sentence, nothing in this Warrant shall be construed to give to any
Person other than the Company and the Holder any legal or equitable right,
remedy or cause of action under this Warrant. This Warrant may be amended only
in writing signed by the Company and the Holder and their successors and
assigns.

          (b)  The Company will not, by amendment of its governing documents or
through any reorganization, transfer of assets, consolidation, merger,
dissolution, issue or sale of securities or any other voluntary action, avoid or
seek to avoid the observance or performance of any of the terms of this Warrant,
but will at all times in good faith assist in the carrying out of all such terms
and in the taking of all such action as may be necessary or appropriate in order
to protect the rights of the Holder against impairment. Without limiting the
generality of the foregoing, the Company (i) will not increase the par value of
any Warrant Shares above the amount payable therefor on such exercise, (ii) will
take all such action as may be reasonably necessary or appropriate in order that
the Company may validly and legally issue fully paid and nonassessable Warrant
Shares on the exercise of this Warrant, and (iii) will not close its shareholder
books or records in any manner which interferes with the timely exercise of this
Warrant.

          (c)  Governing Law; Venue; Waiver Of Jury Trial.  The corporate laws
               ------------------------------------------
of the state of Delaware shall govern all issues concerning the relative rights
of the company and its stockholders. all questions concerning the construction,
validity, enforcement and interpretation of this warrant shall be governed by
and construed and enforced in accordance with the laws of the state of new york.
each party hereby irrevocably submits to the exclusive jurisdiction of the state
and federal courts sitting in the city of New York, Borough of Manhattan, for
the

                                       9
<PAGE>

adjudication of any dispute hereunder or in connection herewith or with any
transaction contemplated hereby or discussed herein (including with respect to
the enforcement of any of the transaction documents), and hereby irrevocably
waives, and agrees not to assert in any suit, action or proceeding, any claim
that it is not personally subject to the jurisdiction of any such court, that
such suit, action or proceeding is improper. Each party hereby irrevocably
waives personal service of process and consents to process being served in any
such suit, action or proceeding by mailing a copy thereof via registered or
certified mail or overnight delivery (with evidence of delivery) to such party
at the address in effect for notices to it under this agreement and agrees that
such service shall constitute good and sufficient service of process and notice
thereof. Nothing contained herein shall be deemed to limit in any way any right
to serve process in any manner permitted by law. The company hereby waives all
rights to a trial by jury.

          (d)  The headings herein are for convenience only, do not constitute a
part of this Warrant and shall not be deemed to limit or affect any of the
provisions hereof.

          (e)  In case any one or more of the provisions of this Warrant shall
be invalid or unenforceable in any respect, the validity and enforceability of
the remaining terms and provisions of this Warrant shall not in any way be
affected or impaired thereby and the parties will attempt in good faith to agree
upon a valid and enforceable provision which shall be a commercially reasonable
substitute therefor, and upon so agreeing, shall incorporate such substitute
provision in this Warrant.

                 [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK;
                            SIGNATURE PAGE FOLLOWS]

                                       10
<PAGE>

     IN WITNESS WHEREOF, the Company has caused this Warrant to be duly executed
by its authorized officer as of the date first indicated above.


                                        MERCATOR SOFTWARE, INC.


                                        By: __________________________
                                        Name:_________________________
                                        Title:________________________

                                       11
<PAGE>

                            FORM OF EXERCISE NOTICE

(To be executed by the Holder to exercise the right to purchase shares of Common
Stock under the foregoing Warrant)

To:  Mercator Software, Inc.

The undersigned is the Holder of Warrant No. _______ (the "Warrant") issued by
Mercator Software, Inc., a Delaware corporation (the "Company").  Capitalized
terms used herein and not otherwise defined have the respective meanings set
forth in the Warrant.

1.  The Warrant is currently exercisable to purchase a total of ______________
    Warrant Shares.

2.  The undersigned Holder hereby exercises its right to purchase
    _________________ Warrant Shares pursuant to the Warrant.

3.  The Holder intends that payment of the Exercise Price shall be made as
    (check one):


                    ____"Cash Exercise" under Section 9(a)

                    ____"Cashless Exercise" under Section 9(b)

4.  If the holder has elected a Cash Exercise, the holder shall pay the sum of
    $____________ to the Company in accordance with the terms of the Warrant.

5.  Pursuant to this exercise, the Company shall deliver to the holder__________
    Warrant Shares in accordance with the terms of the Warrant.

6.  Following this exercise, the Warrant shall be exercisable to purchase a
    total of ______________ Warrant Shares.

Dated:_____________, ___                  Name of Holder:

                                          (Print)____________________________

                                          By:________________________________
                                          Name:______________________________
                                          Title:_____________________________

                                          (Signature must conform in all
                                          respects to name of holder as
                                          specified on the face of the Warrant)
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                              FORM OF ASSIGNMENT

          [To be completed and signed only upon transfer of Warrant]

          FOR VALUE RECEIVED, the undersigned hereby sells, assigns and
transfers unto ________________________________ the right represented by the
within Warrant to purchase ____________ shares of Common Stock of Mercator
Software, Inc. to which the within Warrant relates and appoints ________________
attorney to transfer said right on the books of Mercator Software, Inc. with
full power of substitution in the premises.


Dated:______________, ___

                                      ________________________________________
                                      (Signature must conform in all respects to
                                      name of holder as specified on the face of
                                      the Warrant)
                                      _____________________________________
                                      Address of Transferee

                                      _____________________________________
                                      _____________________________________


In the presence of:

________________________