---
title: "Begin an SSO login flow"
method: POST
path: "/auth/sso/initiate"
tags: ["Auth"]
---

# Begin an SSO login flow

`POST /auth/sso/initiate`

## Request

- Base URL: `https://api.mnemom.ai/v1`
- URL: `https://api.mnemom.ai/v1/auth/sso/initiate`
- Auth: none required

Looks up the SSO provider for the email's domain, generates PKCE + HMAC-signed state, sets a short-lived `mnemom_sso_initiator` cookie, and returns the IdP URL for the SPA to `window.location.href` to.

## Request body

- object
  - `email` string, email, required
  - `redirect_after` string: SPA path to return to after SSO completes (allowlisted).

## Response `200`

IdP URL returned. Also sets `mnemom_sso_initiator` cookie.

- object
  - `url` string, uri, required

## Other responses

- `400`: Bad request
- `403`: Cross-origin write refused (`cross_origin_rejected`). A state-changing request that carries the browser session cookie must come from a first-party origin (`Origin`, or failing that `Referer`) and must not send a form-style body (text/plain, urlencoded, multipart) the operation does not declare. Bearer and API-key callers are never subject to this check.
- `404`: Resource not found
- `429`: Rate-limit exceeded. The global per-IP limiter (100 requests/minute, applied to every `/v1/*` route) rejected this request. Back off until the window resets — `Retry-After` carries the cooldown in seconds and `X-RateLimit-Reset` the absolute reset time.
- `500`: Server error — request was well-formed but the server failed to fulfill it. Typically a downstream dependency (DB / RPC / external API) returned an unexpected error.
- `503`: An upstream dependency is currently unavailable. The request was not processed; retry after the cooldown window.

---

[API](https://skmtc.dev/mnemom/apis/mnemom-api.md) · [All operations](https://skmtc.dev/mnemom/apis/mnemom-api/llms.txt) · [OpenAPI document](https://skmtc.dev/mnemom/apis/mnemom-api/revisions/274b7a6ea182?raw)