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

$249,200.00                                                San Mateo, California
                                                                 August 30, 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 Two Hundred Forty-Nine Thousand Two Hundred Dollars
($249,200.00), 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 August 30, 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
August 30, 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/ David B. Cooper, Jr.
                              ----------------------------------------
                              DAVID B. COOPER, JR.

Source: OneCLE Business Contracts.