> For the complete documentation index, see [llms.txt](https://gitbook.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gitbook.com/docs/developers/gitbook-api/api-reference/organizations/join-an-organization.md).

# Join an organization

Join an organization if the user's verified email domain matches one of the organization's allowed email domains. This endpoint allows existing users to join organizations they're eligible for based on their email domain.

```json
{"openapi":"3.1.0","info":{"title":"GitBook API","version":"0.0.1-beta"},"tags":[{"name":"organizations","description":"The Organizations API provides a robust way to handle the administrative structure of your GitBook workspace. By creating and configuring organizations, you can group multiple users, spaces, and collections, simplifying your permission management and fostering efficient collaboration for teams of any size.\n\n{% openapi-schemas spec=\"gitbook\" schemas=\"Organization\" grouped=\"false\" %}\n    The Organization object\n{% endopenapi-schemas %}\n"}],"servers":[{"url":"{host}/v1","variables":{"host":{"default":"https://api.gitbook.com"}}}],"security":[{"user":[]}],"components":{"securitySchemes":{"user":{"type":"http","scheme":"bearer"}},"parameters":{"organizationId":{"name":"organizationId","in":"path","required":true,"description":"The unique id of the organization","schema":{"$ref":"#/components/schemas/EntityId"}}},"schemas":{"EntityId":{"type":"string","pattern":"^[a-zA-Z0-9_-]+$","description":"A unique entity identifier"}},"responses":{"BadRequestError":{"description":"Bad Request","content":{"application/json":{"schema":{"type":"object","required":["error"],"properties":{"error":{"type":"object","properties":{"code":{"type":"integer","format":"int32","enum":[400]},"message":{"type":"string"}},"required":["code","message"]}}}}}},"NotFoundError":{"description":"Not Found","content":{"application/json":{"schema":{"type":"object","required":["error"],"properties":{"error":{"type":"object","properties":{"code":{"type":"integer","format":"int32","enum":[404]},"message":{"type":"string"}},"required":["code","message"]}}}}}}}},"paths":{"/orgs/{organizationId}/join":{"post":{"operationId":"joinOrganization","summary":"Join an organization","description":"Join an organization if the user's verified email domain matches one of the organization's allowed email domains.\nThis endpoint allows existing users to join organizations they're eligible for based on their email domain.\n","tags":["organizations"],"parameters":[{"$ref":"#/components/parameters/organizationId"}],"responses":{"204":{"description":"Successfully joined the organization"},"400":{"description":"User's email domain is not valid","$ref":"#/components/responses/BadRequestError"},"404":{"description":"Organization not found","$ref":"#/components/responses/NotFoundError"}}}}}}
```


---

# Agent Instructions
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## 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, and the optional `goal` query parameter:

```
GET https://gitbook.com/docs/developers/gitbook-api/api-reference/organizations/join-an-organization.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

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.