Obtain a system access token using client_credentials, then create a partner-managed company via POST /v1/partner_managed_companies
Add the contractor to the company using the Gusto contractor creation endpoint, providing name, SSN or EIN, and payment method
Create an off-cycle payroll using the Gusto payroll endpoints specifying off_cycle: true and the pay period dates
Add contractor payment line items to the off-cycle payroll with the appropriate payment amount and earnings type
Submit the off-cycle payroll for processing via the payroll submission endpoint; confirm the pay date is at least the minimum number of business days in the future for ACH processing
Poll the payroll status endpoint or listen for Gusto webhooks to confirm processing and catch any rejections (e.g., insufficient bank balance, invalid routing number)
Known gotchas
Off-cycle payrolls have stricter submission deadlines than regular payrolls because ACH requires a minimum number of business days — check the Gusto documentation for current minimum lead time before scheduling payments
System access tokens (not partner tokens, which are deprecated as of v2024-04-01) must be used for company-level operations like payroll submission in new integrations
Contractor payments above IRS reporting thresholds will be tracked by Gusto for 1099-NEC filing; confirm 1099 delivery method (e-delivery vs. mail) with the contractor during onboarding
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp