UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): July 22, 2015

Rapid7, Inc.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (617) 247-1717

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

On July 22, 2015, Rapid7, Inc. (the “Company”) issued and sold to entities affiliated with Technology Crossover Ventures an aggregate of 312,500 shares of common stock, par value $0.01 per share (the “Common Stock”), at a purchase price of $16.00 per share for aggregate consideration of $5.0 million (the “Private Placement”). The closing of the Private Placement occurred simultaneously with the closing of the Company’s initial public offering of shares of Common Stock (the “IPO”). The issuances of Common Stock in the Private Placement were made in reliance on Section 4(a)(2) of the Securities Act of 1933, as amended.

Amendment and Restatement of Certificate of Incorporation

On July 22, 2015, the Company filed an amended and restated certificate of incorporation (the “Restated Certificate”) with the Secretary of State of the State of Delaware immediately prior to the closing of the IPO. The Company’s board of directors and stockholders previously approved the Restated Certificate effective as of, and contingent upon the closing of, the IPO.

The foregoing description of the Restated Certificate is qualified in its entirety by reference to the full text of the Restated Certificate, a copy of which is filed as Exhibit 3.1 to this Current Report on Form 8-K and is incorporated herein by reference.

Amendment and Restatement of Bylaws

Effective as of July 22, 2015, the Company adopted amended and restated bylaws (the “Restated Bylaws”) in connection with the closing of the IPO. The Company’s board of directors and stockholders previously approved the Restated Bylaws effective as of, and contingent upon the closing of, the IPO.

The foregoing description of the Restated Bylaws is qualified in its entirety by reference to the full text of the Restated Bylaws, a copy of which are filed as Exhibit 3.2 to this Current Report on Form 8-K and is incorporated herein by reference.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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