---
title: "Begin passkey enrollment — return WebAuthn creation options"
method: POST
path: "/auth/passkey/enroll"
tags: ["Auth"]
---

# Begin passkey enrollment — return WebAuthn creation options

`POST /auth/passkey/enroll`

## Request

- Base URL: `https://api.mnemom.ai/v1`
- URL: `https://api.mnemom.ai/v1/auth/passkey/enroll`
- Auth: one of:
  - API key in cookie `mnemom_session`
  - HTTP bearer

Authenticated endpoint. Returns `PublicKeyCredentialCreationOptions` for the SPA to pass to `navigator.credentials.create()`. Stores the challenge in KV with a 30-second TTL; the companion `/verify-enroll` endpoint consumes it. `excludeCredentials` is pre-populated with the user's existing passkeys so the authenticator prevents duplicate enrollment of the same key.

## Response `200`

WebAuthn creation options. Shape follows the WebAuthn Level 3 spec.

- PublicKeyCredentialCreationOptionsJSON: WebAuthn registration options (base64url-encoded per the WebAuthn Level 3 JSON serialization).
  - `rp` object
  - `user` object
  - `challenge` string
  - `pubKeyCredParams` unknown[]
    - unknown
  - `authenticatorSelection` object
  - `attestation` string
  - `excludeCredentials` unknown[]
    - unknown
  - `timeout` integer

## Other responses

- `400`: Bad request
- `401`: Authentication required
- `403`: Forbidden
- `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)