---
title: "Start SSO"
method: POST
path: "/auth/sso/start"
tags: ["Auth"]
---

# Start SSO

`POST /auth/sso/start`

Initiate a new Single Sign-On (SSO) session. Returns a session URL to be completed with SSO provider credentials.

## Request body

- SsoStartRequest
  - `redirect_to` string, nullable — URL to redirect to after SSO completion
  - `redirect_uri` string, nullable — OAuth redirect URI to use for the SSO provider callback

## Response `200`

Success

- SsoStartResponse
  - `authorization_url` string, required — URL to redirect user to for SSO authentication
  - `state` string, required — State parameter for CSRF protection
  - `redirect_uri` string, required — OAuth redirect URI used for the SSO provider callback

## Other responses

- `400` — Bad Request - The request was malformed or contained invalid data
- `429` — Too Many Requests - You are being rate limited
- `500` — Internal Server Error - An unexpected error occurred

## Changes

> 10 revisions in range; 1 not diffed.

- **2026-09-06** `a52a2cf49d9b` — 16 warning, 100 info
  - added the new `IP_BAN_DECLINED` enum value to the `code` response property for the response status `400`
  - added the new `IP_BAN_DECLINED` enum value to the `code` response property for the response status `500`
  - added the new `PHONE_COUNTRY_NOT_SUPPORTED` enum value to the `code` response property for the response status `400`
  - added the new `PHONE_COUNTRY_NOT_SUPPORTED` enum value to the `code` response property for the response status `500`
  - …112 more
  - …this revision’s changelog is incomplete
- **2026-09-05** `4dbb738a3e22` — 2 info
  - removed the `NSFW_EMOJI_STICKER_BLOCKED` enum value from the `code` response property for the response status `400`
  - removed the `NSFW_EMOJI_STICKER_BLOCKED` enum value from the `code` response property for the response status `500`
- **2026-09-03** `fa36b1b48ca5` — 10 info
  - removed the `INVALID_PACK_TYPE` enum value from the `code` response property for the response status `400`
  - removed the `INVALID_PACK_TYPE` enum value from the `code` response property for the response status `500`
  - removed the `MAX_PACKS` enum value from the `code` response property for the response status `400`
  - removed the `MAX_PACKS` enum value from the `code` response property for the response status `500`
  - …6 more

[Change history](https://skmtc.dev/fluxer/apis/fluxer-api/changes/auth/sso/start/post.md)

---

[API](https://skmtc.dev/fluxer/apis/fluxer-api.md) · [All operations](https://skmtc.dev/fluxer/apis/fluxer-api/llms.txt) · [OpenAPI document](https://skmtc.dev/fluxer/apis/fluxer-api/revisions/e36d9bcd8fbe?raw)