| Document and Entity Information | Dec. 30, 2024 |
| Cover [Abstract] | |
| Entity Registrant Name | SPS COMMERCE INC |
| Amendment Flag | true |
| Entity Central Index Key | 0001092699 |
| Document Type | 8-K/A |
| Document Period End Date | Dec. 30, 2024 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-34702 |
| Entity Tax Identification Number | 41-2015127 |
| Entity Address, Address Line One | 333 South Seventh Street |
| Entity Address, Address Line Two | Suite 1000 |
| Entity Address, City or Town | Minneapolis |
| Entity Address, State or Province | MN |
| Entity Address, Postal Zip Code | 55402 |
| City Area Code | (612) |
| Local Phone Number | 435-9400 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common stock, par value $0.001 per share |
| Trading Symbol | SPSC |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Amendment Description | On January 2, 2025, SPS Commerce, Inc. (the “Company”) filed a Current Report on Form 8-K (the “Original Form 8-K”) with the U.S. Securities and Exchange Commission to report its agreement to issue unregistered shares of its common stock as partial payment for its acquisition (the “Acquisition”) of Carbon6 Technologies, Inc., a Delaware corporation (“Carbon6”) at the closing of the Acquisition. The number of shares to be issued was unknown at the time of the filing of the Original Form 8-K and the Company is filing this Amendment No. 1 to the Original Form 8-K (this “Amendment No. 1”) to report the closing of the Acquisition, the entry into the Registration Rights Agreement (as defined below), and the number of shares of its common stock issued in connection with the closing. The information in this Amendment No. 1 supplements, and does not change, the information contained in the Original Form 8-K. |
