# Farcaster User Profile Lookup

> Farcaster User Profile Lookup is a paid API for AI agents from api.web3identity.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-14).

Retrieves a Farcaster user's profile data including FID, username, display name, and follower count by username, FID, or connected Ethereum address

## Facts

- Endpoint: GET https://api.web3identity.com/api/farcaster/vitalik
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api-web3identity-com-6788680d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_RV90GcPYtPsmbq6W4lVMW

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 api-web3identity-com-6788680d
```

Example prompt: Can you pull up the Farcaster profile for the username 'vitalik' — I want their FID, display name, and how many followers they have?

## When to prefer this

Use this endpoint when you need to resolve a Farcaster identity — by username, FID, or connected wallet address — and retrieve profile metadata such as display name and follower count. Prefer this over general ENS or Web3 identity lookups when the target is specifically a Farcaster social profile.

## Known failure modes

- Username or FID not found — returns 404 or empty result
- Invalid or unlinked Ethereum address returns no profile
- Payment of $0.02 USDC not fulfilled — returns HTTP 402
- Rate limiting or quota exceeded — returns 429
- Malformed input identifier causes 400 error

## How this service works

Get Farcaster user profile by FID, username, or connected address

## Output

Returns a JSON object with the user's Farcaster FID (numeric ID), username, display name, and follower count for the requested user identity

## Example request

```json
{
 "input": {
  "type": "http",
  "method": "GET",
  "queryParams": {}
 }
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "fid": {
       "type": "number"
      },
      "username": {
       "type": "string"
      },
      "followers": {
       "type": "number"
      },
      "displayName": {
       "type": "string"
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/api-web3identity-com-6788680d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.web3identity.com](https://www.zero.xyz/host/api.web3identity.com/llms.txt)