# Neynar Farcaster User Registration

> Neynar Farcaster User Registration is a paid API for AI agents from api.neynar.com, paid per call via x402, $0.0001/call, status unknown (last checked 2026-09-16).

Creates or registers a new Farcaster user account via the Neynar developer platform

## Facts

- Endpoint: POST https://api.neynar.com/v2/farcaster/user/
- Price: $0.0001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/neynar-farcaster-user-registration-76929a6a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_-MA7Tp4pfvEtfEuZA3_in

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability neynar-farcaster-user-registration-76929a6a -d '<json body>'
```

Example prompt: Create a new Farcaster user account for my app user with the username 'alice_web3', display name 'Alice Smith', and bio 'building in web3' — use my Neynar-managed signer.

## When to prefer this

Use this endpoint when you need to programmatically create a new Farcaster user account — particularly for apps that onboard users to Farcaster at scale, managed account flows, or when building Farcaster-native applications that require user registration via Neynar's managed signer infrastructure.

## Known failure modes

- Username already taken — 409 conflict returned
- Invalid or missing Ethereum custody address — 400 bad request
- Farcaster network registration failure — 503 service unavailable
- Insufficient payment or x402 payment not processed — 402 payment required
- Rate limit exceeded — 429 too many requests
- Invalid API key or unauthorized — 401 unauthorized

## How this service works

Complete Farcaster developer platform

## Output

Returns the newly created Farcaster user object including the assigned FID (Farcaster ID), username, display name, profile metadata, and signer UUID that can be used to perform actions on behalf of the user.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/neynar-farcaster-user-registration-76929a6a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.neynar.com](https://www.zero.xyz/host/api.neynar.com/llms.txt)