Argyle vs Gusto

Argyle

Graded on the REST API. One OpenAPI file covers 91 operations, llms.txt indexes Markdown docs, and a Sandbox with sample users comes with a Console sign-up. Every payroll connection needs the worker to sign in through Link. No prices are published, no idempotency keys were found, and API keys carry no per-key scopes.

Gusto

This listing covers the Embedded Payroll API. Every reference page carries an OpenAPI 3.1 definition, payroll is calculated as a preview before submission, and each API version gets 12 months of deprecation support. Production needs commercial and security approval, no price was readable, and the status page lists 11 incidents between 14 July and 5 October 2026, five marked major.

Argyle

1. Send HTTP Basic auth with api_key_id as the username and api_key_secret as the password. Sandbox keys fail with 401 on Production and the reverse
2. Create the user with POST /v2/users and an external_id, then look it up by external_id before retrying. No idempotency key was found
3. Do not read data straight after an account connects. Wait for the account and data webhooks, or for the verification status, before fetching records
4. Follow the full URL in next when paging. Do not build cursor values or fetch pages in parallel. limit defaults to 10 and stops at 200
5. Stay under 50 requests a second. On 429, queue the request and retry later, not at once
6. Treat DELETE /v2/users/{id} as permanent. It removes every resource tied to that user, with no confirmation step

Gusto

1. Develop against https://api.gusto-demo.com. Production at https://api.gusto.com needs keys Gusto issues after its reviews
2. Send X-Gusto-API-Version: 2026-06-15 on every call. Without it the application's minimum version applies
3. Send the resource's current version with every PUT, and only the fields to change. A stale version returns 409
4. Calculate and submit return 202. Poll GET on the payroll until calculated_at is set or the status is processed, and read submission_blockers first
5. For a company already on Gusto, the Embedded API is the wrong route. Use the Gusto CLI or the MCP server at https://mcp.api.gusto.com, which draft payroll but can't submit it