UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 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): January 9, 2015

DEMANDWARE, INC.

(Exact Name of Registrant as Specified in Charter)

Registrant’s telephone number, including area code: (888) 553-9216

Not Applicable

(Former Name or Former Address, if Changed Since Last Report)

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 (see General Instruction A.2. below):

Item 1.01. Entry into a Material Definitive Agreement.

On January 9, 2015, Demandware, Inc., a Delaware corporation (the “Company”), entered into an Agreement and Plan of Merger (the “Agreement”), by and among the Company, Augusta AC Corp., a Delaware corporation and a direct wholly-owned subsidiary of the Company (“Merger Sub”), Tomax Corporation, a Delaware corporation (“Tomax”), and a representative of the selling equityholders of Tomax.

Pursuant to the Agreement, the Company agreed, upon the satisfaction or waiver of the conditions in the Agreement, to acquire all of the outstanding capital stock and vested stock options of Tomax for approximately $60 million in cash payable at the closing, subject to certain adjustments and transaction-related payments (the “Cash Consideration”). The Agreement provides for the payment to the Tomax equityholders of up to an additional $15 million in cash and/or in shares of Company common stock upon the achievement of certain milestones relating to the continued post-closing employment of certain key employees of Tomax. A portion of the Cash Consideration will be held in escrow to secure certain indemnification and other obligations of the sellers.

Each of the Company and Tomax has agreed to customary representations, warranties and covenants in the Agreement. The representations and warranties survive for a period of 24 months after the consummation of the merger, subject to specified exceptions. The Agreement also includes indemnification obligations in favor of the Company from the sellers, including for breaches of representations, warranties, covenants and agreements made by Tomax in the Agreement. The closing of the transaction is conditioned upon customary closing conditions.

The foregoing description of the transactions contemplated by the Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Agreement, a copy of which is attached hereto as Exhibit 2.1 and incorporated herein by reference.

On January 12, 2015, the Company issued a press release announcing that the Company has agreed to acquire Tomax. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

Item 9.01. Exhibits.

SIGNATURE

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.

EXHIBIT INDEX