Exhibit 24

                               POWER OF ATTORNEY

      The undersigned, as a Section 16 reporting person of HashiCorp, Inc. (the
"Company"), hereby constitutes and appoints Paul Warenski, Jeff Schmidt, and
Werner Schwock and each of them, as the undersigned's true and lawful attorney-
in-fact to:

      1.  prepare, execute in the undersigned's name and on the undersigned's
behalf, and submit to the Securities and Exchange Commission (the "SEC") a Form
ID, including amendments thereto, and any other documents necessary or
appropriate to obtain EDGAR codes and passwords enabling the undersigned to make
electronic filings with the SEC of reports required by Section 16(a) of the
Securities Exchange Act of 1934 or any rule or regulation of the SEC;

      2.  complete and execute Forms 3, 4 and 5 and other forms and all
amendments thereto as such attorneys-in-fact shall in their discretion determine
to be required or advisable pursuant to Section 16 of the Securities Exchange
Act of 1934 (as amended) and the rules and regulations promulgated thereunder,
or any successor laws and regulations, as a consequence of the undersigned's
ownership, acquisition or disposition of securities of the Company; and

      3.  do all acts necessary in order to file such forms with the SEC, any
securities exchange or national association, the Company and such other person
or agency as the attorneys-in-fact shall deem appropriate.

      The undersigned hereby ratifies and confirms all that said attorneys-in-
fact and agents shall do or cause to be done by virtue hereof.  The undersigned
acknowledges that the foregoing attorneys-in-fact, in serving in such capacity
at the request of the undersigned, are not assuming, nor is the Company
assuming, any of the undersigned's responsibilities to comply with Section 16 of
the Securities Exchange Act of 1934 (as amended).

      This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file Forms 3, 4 and 5 with respect to the
undersigned's holdings of and transactions in securities issued by the Company,
unless earlier revoked by the undersigned in a signed writing delivered to the
Company and the foregoing attorneys-in-fact.

      IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to
be executed as of this 2nd day of November, 2021.


                                            Signature:  /s/ Armon Dadgar
                                                       ------------------------
                                            Print Name:  Armon Dadgar