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                                                                   EXHIBIT 10.20

                               Pledge Agreement

     THIS PLEDGE AGREEMENT is entered into this 27th day of March, 2000 by and
between AVANTGO. INC., a Delaware corporation (the "Company") and THOMAS HUNTER
(the "Borrower").

     Section 1.  In order to secure payment of the promissory note dated March
27, 2000 (the "Note") payable to the Company, at its principal offices in the
principal amount of One Hundred Three Thousand Three Hundred Eleven Dollars and
Twenty-Five Cents ($103,311.25), which Note the Borrower delivered in connection
with a loan extended to the Borrower by the Company, the Borrower hereby grants
the Company a security interest in, and assigns, transfers and pledges to the
Company, the following securities and other property:

          (a) The stock certificate evidencing Fifty-Nine Thousand Thirty-Five
(59,035) shares of the Company's Common Stock (the "Common Stock") delivered to
and deposited with the Company as collateral for the Note; and

          (b) Any and all new, additional or different securities or other
property subsequently distributed with respect to the shares identified in
Subsection (a) above that are to be delivered to and deposited with the Company
pursuant to the requirements of Section 4 of this Agreement; and

          (c) Any and all other property and money that is delivered to or comes
into the possession of the Company pursuant to the terms and provisions of this
Agreement; and

          (d) [The Individual Retirement Account (the "Account") maintained at
Salomon Smith Barney in the name of Thomas Hunter, account number 494-67074-12;]
and

          (e) The proceeds of any sale, exchange or disposition of the property
and securities described in Subsection (a), Co), (c) or (d) above.

All securities, property and money to be assigned to, transferred to and pledged
with the Company shall be herein referred to as the "Collateral" and, in the
case of the securities, shall be accompanied by one or more stock power
assignments properly endorsed by the Borrower. The Company shall hold the
Collateral in accordance with the terms and provisions of this Agreement.

     Section 2.  Warranties. The Borrower hereby warrants that the Borrower is
the owner of the Collateral and has the right to pledge the Collateral and that
the Collateral is free from all liens, advance claims and other security
interests (other than those created hereby).

     Section 3.  Rights and Powers. The Company may, without obligation to do
so, exercise one or more of the following rights and powers with respect to the
Collateral:

Confidential treatment has been requested for portions of this exhibit. The copy
filed herewith omits the information subject to the confidentiality request.
Omissions are designated as ****. A complete version of this exhibit has been
filed separately with the Securities and Exchange Commision.

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          (a) Accept in its discretion, but subject to the applicable
limitations of Section 9, other property of the Borrower in exchange for all or
part of the Collateral and release Collateral to the Borrower to the extent
necessary to effect such exchange, and in such event the money, property or
securities received in the exchange shall be held by the Company as substitute
security for the Note and all other indebtedness secured hereunder;

          (b) Perform such acts as are necessary to preserve and protect the
Collateral and the rights, powers and remedies granted with respect to such
Collateral by this Agreement; and

          (c) Transfer record ownership of the Collateral to the Company or its
nominee add receive, endorse and give receipt for, or collect by legal
proceedings or otherwise, dividends or other distributions made or paid with
respect to the Collateral, but only if there exists at the time an outstanding
event of default under Section 10 of this Agreement.

          Any action by the Company pursuant to the provisions of this Section 3
may be taken without notice to the Borrower. Expenses reasonably incurred in
connection with such action shall be payable by the Borrower and form part of
the indebtedness secured hereunder, as provided in Section 12.

          So long as there exists no event of default under Section 10 of this
Agreement, the Borrower may exercise all shareholder voting rights and be
entitled to receive any and all regular cash dividends paid on the Collateral.
Accordingly, until such time as an event of default occurs under this Agreement,
all proxy statements and other shareholder materials pertaining to the
Collateral shall be delivered to the Borrower at the address indicated below.

          Any cash sums that the Company may receive in the exercise of its
rights and powers under this Section 3 shall be applied to the payment of the
Note and any other indebtedness secured hereunder, in such order of application
as the Company deems appropriate. Any remaining cash shall be paid over to the
Borrower.

     Section 4.  Duty to Deliver. Any new, additional or different securities
that may now or hereafter become distributable with respect to the Collateral by
reason of (i) any stock dividend, stock split or reclassification of the capital
stock of the Company or (ii) any merger, consolidation or other reorganization
affecting the capital structure of the Company shall, upon receipt by the
Borrower, be promptly delivered to and deposited with the Company as part of the
Collateral hereunder. Such securities shall be accompanied by one or more
properly endorsed stock power assignments.

     Section 5.  Care of Collateral. The Company shall exercise reasonable care
in the custody and preservation of the Collateral but shall have no obligation
to initiate any action with respect to, or otherwise inform the Borrower of, any
conversion, call, exchange right, preemptive right, subscription right, purchase
offer or other right or privilege relating to or affecting the Collateral;
provided, however, that the Company will notify the Borrower of any such rights
of the Borrower to protect against adverse claims or to protect the Collateral
against the possibility of a decline in market value. The Company shall not be
obligated to take any action with respect to the

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Collateral requested by the Borrower unless the request is made in writing and
the Company determines that the requested action will not unreasonably
jeopardize the value of the Collateral as security for the Note and other
indebtedness secured hereunder.

          The Company may at any time release and deliver all or part of the
Collateral to the Borrower, and the receipt thereof by the Borrower shall
constitute a complete and full acquittance for the Collateral so released and
delivered. The Company shall accordingly be discharged from any further
liability or responsibility for the Collateral, and the released Collateral
shall no longer be subject to the provisions of this Agreement. However, any and
all releases of the Collateral shall be effected in compliance with the
applicable limitations of Section 9(a) and (c).

     Section 6.  Payment of Taxes and Other Charges. The Borrower shall pay,
prior to the delinquency date, all taxes, liens, assessments and other charges
against the Collateral, and in the event of the Borrower's failure to do so, the
Company may at its election pay any or all of such taxes and charges without
contesting the validity or legality thereof. The payments so made shall become
part of the indebtedness secured hereunder and, until paid, shall bear interest
at the minimum per annum rate, compounded annually, required to avoid the
imputation of interest income to the Company and compensation income to the
Borrower under the federal tax laws.

     Section 7.  Covenants of Borrower. Borrower will not (a) sell, assign,
convoy, lease or otherwise transfer or permit the transfer of the Collateral, or
any interest therein; or (b) create, permit or suffer to exist any mortgage,
pledge, hypothecation, assignment, security interest, lien charge or encumbrance
or preference, priority or other security agreement or arrangement of any kind
or nature whatsoever, in the Collateral, or any interest thereto.

     Section 8.  Transfer of Collateral. In connection with the transfer or
assignment of the Note (whether by negotiation, discount or otherwise), the
Company may transfer all or any part of the Collateral, and the transferee shall
thereupon succeed to all the rights, powers and remedies granted the Company
hereunder with respect to the Collateral so transferred, Upon such transfer, the
Company shall be fully discharged from all liability and responsibility for the
transferred Collateral.

     Section 9.  Release of Collateral. Provided (i) all indebtedness secured
hereunder (other than payments not yet due and payable under the Note) shall at
the time have been paid in full or cancelled and (ii) there does not otherwise
exist any event of default under Section 10, the pledged shares of Common Stock,
together with any additional Collateral that may hereafter be pledged and
deposited hereunder, shall be released from pledge and returned to the Borrower
in accordance with the following provisions:

          (a) Upon payment or prepayment of principal under the Note, together
with payment of all accrued interest to date, one or more shares of Common Stock
held as Collateral hereunder shall (subject to the limitation of Subsection (d)
below) be released to the Borrower within three days after such payment or
prepayment. The number of shares to be so released shall be equal to the number
obtained by multiplying (i) the total number of shares of Common Stock held
under this Agreement at the time of the payment or prepayment by (ii) a
fraction, the numerator of which

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shall be the amount of the principal paid or prepaid and the denominator of
which shall be the unpaid principal balance of the Note immediately prior to
such payment or prepayment. In no event, however, shall any fractional shares be
released.

          (b) One or more shares of Common Stock held as Collateral hereunder
shall (subject to the limitation of Subsection (d) below) be released to a
stockbroker designated in writing by the Borrower and acceptable to the Company
for the sole purpose of effecting an immediate sale of the released shares,
provided that such stockbroker agrees to forward any proceeds (up to the balance
of principal and interest due under the Note) directly to the Company to be used
to satisfy the Note.

          (c) Any additional Collateral that may hereafter be pledged and
deposited with the Company (pursuant to the requirements of Section 4) with
respect to the shares of Common Stock pledged hereunder shall be released at the
same time the particular shares of Common Stock to which the additional
Collateral relates are to be released in accordance with the applicable
provisions of Subsection (a) or (b) above. Under no circumstances, however,
shall any shares of Common Stock or any other Collateral be released if
previously applied to the payment of any indebtedness secured hereunder.

          (d) In no event shall any shares of Common Stock be released pursuant
to the provisions of Subsections (a), (b) and (c) above if, and to the extent,
the fair market value of the Common Stock and all other Collateral that would
otherwise remain in pledge hereunder after such release is effected would be
less than the unpaid balance of the Note (principal and accrued interest).

     Section 10.  Events of Default. The occurrence of one or more of the
following events shall constitute an event of default under this agreement:

          (a) The failure of the Borrower to pay the principal and accrued
interest when due under the Note;

          (b) The failure of the Borrower to perform a material obligation
imposed upon the Borrower by reason of this Agreement; or

          (c) The breach of may covenant, representation or warranty of the
Borrower contained in this Agreement.

          Upon the occurrence of any such event of default, the Company may, at
its election, declare the Note and all other indebtedness secured hereunder to
be immediately due and payable and may exercise any or all of the rights and
remedies granted to a secured party under the provisions of the California
Uniform Commercial Code (as now or hereafter in effect), including (without
limitation) the power to dispose of the Collateral by public or private sale or
to accept the Collateral in full payment of the Note and all other indebtedness
secured hereunder.

          Any proceeds realized from the disposition of the Collateral pursuant
to the foregoing power of sale shall be applied first to the payment of
reasonable expenses incurred by the Company in connection with the disposition,
then to the payment of the Note and finally to any other indebtedness secured
hereunder. Any surplus proceeds shall be paid over to the Borrower.

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However, in the event such proceeds prove insufficient to satisfy all
obligations of the Borrower under the Note, then the Borrower shall remain
personally liable for the resulting deficiency.

     Section 11.  Other Remedies. The rights, powers and remedies granted to the
Company and the Borrower pursuant to the provisions of this Agreement shall be
in addition to all rights, powers and remedies granted to the Company and the
Borrower under any statute or rule of law. Any forbearance, failure or delay by
the Company or the Borrower in exercising any right, power or remedy under this
Agreement shall not be deemed to be a waiver of such right, power or remedy. Any
single or partial exercise of any right, power or remedy under this Agreement
shall not preclude the further exercise thereof, and every right, power and
remedy of the Company and the Borrower under this Agreement shall continue in
full force and effect, unless such right, power or remedy is specifically waived
by an instrument executed by the Company or the Borrower, as the case may be.

     Section 12.  Costs and Expenses. All reasonable costs and expenses
(including reasonable attorneys fees) incurred by the Company in the exercise or
enforcement of any right, power or remedy granted it under this Agreement shall
become part of the indebtedness secured hereunder and shall constitute a
personal liability of the Borrower payable immediately upon demand and bearing
interest until paid at the Company's bank interest rate then being earned by the
Company on its deposits.

     Section 13.  Applicable Law. This Agreement shall be governed by and
construed in accordance with the laws of the State of California and shall be
binding upon the executors, administrators, heirs and assigns of the Borrower.

     Section 14.  Arbitration. Any controversy between the parties hereto
involving the construction or application of any terms, covenants or conditions
of this Agreement or the Note, or any claims arising out of or relating to this
Agreement or the Note, or the breach hereof or thereof, will be submitted to and
settled by final and binding arbitration in San Francisco, California, in
accordance with the rules of the American Arbitration Association then in
effect, and judgment upon the award rendered by the arbitrator may be entered in
any court having jurisdiction thereof. In the event of any arbitration under
this Agreement or the Note, the prevailing party shall be entitled to recover
from the losing party reasonable expenses, attorneys' fees and costs incurred
therein or in the enforcement or collection of any judgment or award rendered
therein. The "prevailing party" means the party determined by the arbitrator to
have most nearly prevailed, even if such party did not prevail in all matters,
not necessarily the one in whose favor a judgment is rendered.

     Section 15.  Severability. If any provision of this Agreement is held to be
invalid under applicable law, then such provision shall be ineffective only to
the extent of such invalidity, and neither the remainder of such provision nor
any other provisions of this Agreement shall be affected thereby.

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          IN WITNESS WHEREOF, this Agreement has been executed by the Borrower
on this 27th day of March, 2000.

                                    /s/ Thomas Hunter
                                    ------------------------------
                                    THOMAS HUNTER

                       Address:     [******]
                                    ------------------------------
                                    [******]
                                    ------------------------------

Agreed to and Accepted by:

AVANTGO, INC.

By: /s/ Richard Owen
   -----------------------------------
Richard Owen, Chief Executive Officer

Dated: March 27, 2000

****** Certain information on this page has been omitted and filed separately
with the Securities and Exchange Commission. Confidential treatment has been
requested with respect to the omitted portions.

                                      -6-<PAGE>

                                                                   EXHIBIT 10.21

                                PROMISSORY NOTE
                                ---------------

$103,311.25                                                San Mateo, California
                                                                  March 27, 2000

          For value received, the undersigned (the "Borrower") promises to pay
AvantGo, Inc., a Delaware corporation (the "Company"), at its principal office
                                            -------
the principal sum of One Hundred Three Thousand Three Hundred Eleven Dollars and
Twenty Five Cents ($103,311.25), with interest from the date hereof at a rate of
six percent (6%) per annum, compounded semiannually, on the unpaid balance of
such principal sum.  Such principal and interest shall be due and payable on
April 4, 2005 (the "Maturity Date"), provided that if the Maturity Date occurs
during (i) the "lock-up" period following an Initial Public Offering of the
Company's securities, or (ii) the period of time following a "Change of Control"
(as defined in the Stock Option Agreement (the "Option Agreement") dated as of
September 21, 1999 between the undersigned and the Company) in which Borrower's
ability to sell shares of the Company's capital stock is prohibited, the
Maturity Date shall be extended until the date on which such lock-up period or
prohibition expires.

          Notwithstanding the foregoing, the entire unpaid principal sum and
unpaid interest under this Note shall become immediately due and payable upon:
(a) the date when the Borrower ceases to be employed by the Company; (b) the
failure of the Borrower to pay when due the principal balance and accrued
interest on this Note and the continuation of such default for more than thirty
(30) days; (c) the insolvency of the Borrower, the commission of an act of
bankruptcy by the Borrower, the execution by the Borrower of a general
assignment for the benefit of creditors, or the filing by or against the
Borrower of a petition in bankruptcy or a petition for relief under the
provisions of the federal bankruptcy act or another state or federal law for the
relief of debtors and the continuation of such petition without dismissal for a
period of ninety (90) days or more; or (d) the occurrence of a material event of
default under the Pledge Agreement securing this Note or any obligation secured
thereby.

          Principal and interest are payable in lawful money of the United
States of America.  AMOUNTS DUE UNDER THIS NOTE MAY BE PREPAID AT ANY TIME
WITHOUT PENALTY.

          Should suit be commenced to collect any sums due under this Note, such
sum as the Court may deem reasonable shall be added hereto as attorneys' fees.
The makers and endorsers have severally waived presentment for payment, protest,
notice of protest, and notice of nonpayment of this Note.

          This Note, which is full recourse with respect to 100% of the
principal balance hereof, is secured by a pledge of certain contractual rights,
together with any and all shares of Common Stock of the Company then held by the
undersigned, and is subject to the terms of a Pledge Agreement between the
undersigned and the Company of even date herewith.

                              /s/ Thomas Hunter
                              ----------------------------------------
                              THOMAS HUNTER

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