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EXHIBIT 31.1 CERTIFICATION OF CHIEF EXECUTIVE OFFICER AS ADOPTED PURSUANT TO
SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002 I, John Kunze, certify that: 1. I have reviewed this annual report on Form 10-K of Plumtree Software, Inc. 2. Based on my knowledge, this report does not contain any untrue statement of
a material fact or omit to state a material fact necessary to make the statements made, in light of
the circumstances under which such statements were made, not misleading with respect to the period
covered by this report. 3. Based on my knowledge, the financial statements, and other financial
information included in this report, fairly present in all material respects the financial
condition, results of operations and cash flows of the registrant as of, and for, the periods
presented in this report; 4. The registrants other certifying officer(s) and I are responsible for
establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules
13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act
Rules 13a-15(f) and 15d-15(f)) for the registrant and have: a. Designed such disclosure controls and procedures, or caused
such disclosure controls and procedures to be designed under our
supervision, to ensure that material information relating to the
registrant, including its consolidated subsidiaries, is made known
to us by others within those entities, particularly during the
period in which this report is being prepared; b. Designed such internal control over financial
reporting, or caused such internal control over financial reporting
to be designed under our supervision, to provide reasonable
assurance regarding the reliability of financial reporting and the
preparation of financial statements for external purposes in
accordance with generally accepted accounting principles; c. Evaluated the effectiveness of the registrants disclosure
controls and procedures and presented in this report our conclusions
about the effectiveness of the disclosure controls and procedures,
as of the end of the period covered by this report based on such
evaluation; and d. Disclosed in this report any change in the registrants
internal control over financial reporting that occurred during the
registrants most recent fiscal quarter (the registrants fourth
fiscal quarter in the case of an annual report) that has materially
affected, or is reasonably likely to materially affect, the
registrants internal control over financial reporting; 5. The registrants other certifying officer(s) and I have disclosed, based on
our most recent evaluation of internal control over financial reporting, to the registrants
auditors and the audit committee of the registrants board of directors (or persons performing due
equivalent functions): a. All significant deficiencies in the design or operation of
internal controls over financial reporting which are reasonably
likely to adversely affect the registrants ability to record,
process, summarize and report financial information; and b. Any fraud, whether or not material, that involves management
or other employees who have a significant role in the registrants
internal control over financial reporting. Date: March 11, 2005 By: /s/ John KunzeName: John KunzeTitle: Chief Executive Officer
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