---
title: "beginPasskeyAuthentication"
method: POST
path: "/v2/users/public/passkeys:authenticateBegin"
tags: ["User V2"]
---

# beginPasskeyAuthentication

`POST /v2/users/public/passkeys:authenticateBegin`

Begin passkey authentication flow. Returns WebAuthn options and a signed challenge token.

## Request body

- object
  - `email` string, email, required

## Response `200`

WebAuthn authentication options

- PasskeyAuthenticationOptions
  - `options` object — WebAuthn PublicKeyCredentialRequestOptions
  - `challenge_token` string — Signed JWT containing the challenge

## Other responses

- `404` — User not found or no passkeys registered

---

[API](https://skmtc.net/epilot/apis/user-api.md) · [All operations](https://skmtc.net/epilot/apis/user-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/epilot/user-api/versions/7fae886a3c99/schema)