> ## Documentation Index
> Fetch the complete documentation index at: https://docs.symmetry.com/llms.txt
> Use this file to discover all available pages before exploring further.

# I-9 API overview

> Base URLs, authentication, and the tools (live Swagger and a Postman collection) for working with the Symmetry I-9 API.

The Symmetry I-9 API manages employers, employees, form submissions, and E-Verify cases for Form I-9 completion. The endpoint reference in this section is generated from the I-9 OpenAPI specification.

## Environments and base URLs

| Environment | Base URL                              |
| ----------- | ------------------------------------- |
| Production  | `https://api.symmetry.com/i9`         |
| Staging     | `https://api-staging.symmetry.com/i9` |

<Info>
  Always develop and test against the **staging** environment before pointing your integration at production.
</Info>

## Authentication

Make a request to the `/authentication` endpoint using your API key. This returns a valid access token, which you then send on every other request.

<Warning>
  **Access token versus API key**

  Your access token is not the same as your API key. The API key is used for initial authentication to obtain an access token from the `/authentication` endpoint. The access token is then used to authorize and interact with the other I-9 API endpoints securely.
</Warning>

## Try it live with Swagger

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

<Card title="Production Swagger" href="https://api.symmetry.com/i9/docs" icon="play">
  Live API explorer for every I-9 endpoint.
</Card>

### Step 1: Generate an access token

Make a request to the `/authentication` endpoint using your API key. This returns a valid access token.

### Step 2: Authorize in Swagger

* Select the **Authorize** button on the right side of the Swagger UI.
* Paste your access token into the dialog box.
* Select **Authorize**.

Once authorized, an unlocked icon appears next to each endpoint, indicating that you can now send requests.

### Step 3: Try out endpoints

* Select an endpoint.
* Select **Try it out**.
* Select **Execute**.

Swagger displays the API's response.

## Next steps

<CardGroup cols={2}>
  <Card title="Postman" icon="mailbox" href="/i9/api-reference/postman-collection">
    Download the I-9 Postman collection and environment directly from the API.
  </Card>

  <Card title="Endpoints" icon="list" href="/i9/api-reference/employer/returns-a-list-of-all-employers-for-account">
    Full reference for every employer, employee, admin, and E-Verify endpoint.
  </Card>
</CardGroup>