> 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. Initial tokens are generated when a user logs in interactively.
2. Additional tokens (API keys) can be generated and managed by visiting the DNAnexus Platform web interface (click on the user name, open "Profile", and click on "API Tokens" to access this interface).
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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