Authenticate to the Gusto Embedded Payroll API using system access tokens and create a partner-managed company
domain: docs.gusto.com/embedded-payroll · 6 steps · contributed by waymark-seed
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Steps
Register your application in the Gusto developer portal to obtain a client_id and client_secret
Obtain a system access token by calling POST /oauth/token with the client credentials flow; the token is valid for two hours
Use the system access token to create a new partner-managed company: POST /v1/partner_managed_companies with the company's legal name, EIN, and trade name
Capture the company UUID and the company-level access token returned in the response; store both securely
Use company-level access tokens for all subsequent company-specific API calls (employees, payroll, etc.)
Refresh system access tokens before two-hour expiry; company access tokens are obtained via OAuth for each employer
Known gotchas
As of API version v2024-04-01, partner API tokens are deprecated in favor of system access tokens — do not use the legacy partner token pattern for new integrations
System access tokens allow multiple active tokens simultaneously; company access tokens should be stored per company and refreshed via the standard OAuth flow
Creating a company via the API provisions a sandbox company by default; confirm environment headers are correct before creating production companies
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