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The hosted STE web API is a JSON HTTP service that Symmetry runs for you. Send a PayCalcRequest describing one or more employees and receive a PayCalcResponse with the calculated taxes. The endpoint reference in this section is generated from the live OpenAPI specification.
This section documents the hosted Web API specifically. If you use the on-premise SDKs (Java, .NET, or C/C++), you call the engine through their native bindings rather than these REST endpoints — the identifiers for each interface are listed side by side in the reference tables. The concepts, wage types, options, and codes apply to every interface; only the request/response mechanics on this page are hosted-API-only.
New to the hosted API? Start with the Hosted API quickstart for a complete first request, then use this reference for the full endpoint and schema details.

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Environments and base URLs

Staging and production are fully separate — including API keys. Always build and test against staging first. Both environments expose v1 and v2 paths (for example, /ste-hosted/v1/payCalc).

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Authentication

Pass your key as the raw value of the Authorization header — no Bearer prefix, no x-api-key, and no query string. Your API key is issued by Symmetry’s Client Success team; a staging key will not work against production.
Authorization: Bearer <key>, ApiKey <key>, x-api-key, and ?apiKey= are all rejected. Use the raw key as the header value.

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Try it with live Swagger

For interactive, authenticated calls against the running service, use the hosted Swagger UI. It mirrors the endpoints documented in this section and lets you execute real requests.

Production Swagger

Live API explorer for the production environment.

Staging Swagger

Live API explorer for the staging environment.
To authorize in Swagger, select Authorize, paste your Symmetry STE API key for that environment (production key for the production docs, staging key for the staging docs), and select Authorize again. The Authorization header expects the raw key with no Bearer prefix. Once authorized, each endpoint shows an unlocked icon — select an endpoint, choose Try it out, then Execute to see the response.

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Postman collection

Prefer Postman? Download our ready-made collection and environment, with payCalcRequest examples for federal, state, city, county, and multi-state scenarios.

Postman collection & environment

Sample requests for every endpoint, plus the environment variables you’ll need.