Gusto API
Gusto exposes two documented REST surfaces: an App Integrations API with per-merchant OAuth 2.0 grants and an Embedded Payroll API with React SDK flows. Portal signup and the demo environment are self-serve; production access follows a commercial and security review with the partnerships team.
Frequently asked questions
Gusto scores A on the API Report Card. Gusto exposes two documented REST surfaces: an App Integrations API with per-merchant OAuth 2.0 grants and an Embedded Payroll API with React SDK flows. Portal signup and the demo environment are self-serve; production access follows a commercial and security review with the partnerships team.
Gusto has a workable official integration path. Most engineering teams can build against it directly. Open API: self-serve, documented, with SDKs
Gusto is a cloud-native payroll, benefits, and HR platform for small and mid-sized U.S. businesses.
Vertical: Enterprise / HR / ERP (SMB payroll & HR). Running scheduled and off-cycle payroll runs with automatic federal, state, and local tax filing. Generating and distributing W-2s, 1099s, and year-end tax forms.
Very high within the SMB payroll segment.
Employee PII (SSN, DOB, address, bank account, routing numbers). Wages, salaries, bonuses, commissions, equity comp. Federal/state/local tax withholdings and filings (941, 940, W-2, W-3, 1099-NEC, state UI).
Founded December 13, 2011 (~14 years old as of 2026). Cloud-native, mobile-friendly, modern React-based UI, and one of the more developer-forward SMB payroll vendors.
Grades measure one thing: can a customer's engineering team get their own data out programmatically? We check six things (whether a real API exists, how access is gated, data coverage, auth quality, docs and developer experience, and stability) and roll them into a letter grade. Grades get re-verified, and they only move on evidence.