# Neynar Farcaster User Lookup by Username

> Neynar Farcaster User Lookup by Username is a paid API for AI agents from api.neynar.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Retrieves a Farcaster user's profile and account details by their username

## Facts

- Endpoint: GET https://api.neynar.com/v2/farcaster/user/by_username
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/neynar-farcaster-user-lookup-by-username-a29944e3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_HW2cxPeut58hiYgRUhCro

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-lookup-by-username-a29944e3
```

Example prompt: Can you look up the Farcaster profile for the username 'dwr' — I need their FID, bio, follower count, and any verified Ethereum addresses linked to their account?

## When to prefer this

Use this endpoint when you need to resolve a Farcaster handle to a full user profile, FID, or linked wallet addresses. Prefer this over searching by FID when you have a human-readable username as the starting point. Ideal for onboarding flows, social graph enrichment, or cross-referencing Farcaster identities with Ethereum addresses.

## Known failure modes

- Username not found — returns 404 with error message
- Invalid or missing username parameter — returns 400 bad request
- Payment not provided or insufficient — returns 402 payment required
- Rate limit exceeded — returns 429 too many requests
- Farcaster network unavailable — returns 503 service unavailable

## How this service works

Complete Farcaster developer platform

## Output

Returns a Farcaster user object containing the user's FID, username, display name, profile bio, follower and following counts, profile picture URL, custody address, and verified Ethereum wallet addresses.

## Example request

```json
{
 "username": "dwr"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/neynar-farcaster-user-lookup-by-username-a29944e3/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)