> For the complete documentation index, see [llms.txt](https://documentation.dnanexus.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://documentation.dnanexus.com/developer/api/authentication.md).

# Authentication

DNAnexus API calls are protected resources reached by authenticated requests. Clients must make authenticated requests with a "bearer token" using the "Authorization" request header field with the "Bearer" HTTP authorization scheme, for example:

```
Authorization: Bearer 7Fjfp0ZBr1KtDRbnfVdmIw
```

Bearer tokens are generated in three different ways:

1. The system generates a token when a user [logs in interactively](/user/login-and-logout.md), through the UI or the CLI.
2. Users can [generate additional tokens](/user/login-and-logout.md#generating-a-token) in the DNAnexus Platform web interface, scoped to either all projects (a full-scope token) or specific projects.
3. A job launched within the [Execution Environment](/developer/apps/execution-environment.md) is provided with its own token. This token is derived internally by the platform from the original token retrieved with method 1 or 2.


---

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