# 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, e.g.

```
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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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://documentation.dnanexus.com/developer/api/authentication.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.