Neynar Documentation

Fetch fresh FID

Fetch fresh FID

cURL

curl --request GET \
  --url https://api.neynar.com/v2/farcaster/user/fid/ \
  --header 'x-api-key: NEYNAR_API_DOCS' \
  --header 'x-wallet-id: <x-wallet-id>'

import requests

url = "https://api.neynar.com/v2/farcaster/user/fid/"

headers = {
    "x-wallet-id": "<x-wallet-id>",
    "x-api-key": "NEYNAR_API_DOCS"
}

response = requests.get(url, headers=headers)

print(response.text)

const options = {
  method: 'GET',
  headers: {'x-wallet-id': '<x-wallet-id>', 'x-api-key': 'NEYNAR_API_DOCS'}
};

fetch('https://api.neynar.com/v2/farcaster/user/fid/', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.neynar.com/v2/farcaster/user/fid/",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "GET",
  CURLOPT_HTTPHEADER => [
    "x-api-key: NEYNAR_API_DOCS",
    "x-wallet-id: <x-wallet-id>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
    "fmt"
    "net/http"
    "io"
)

func main() {

url := "https://api.neynar.com/v2/farcaster/user/fid/"

req, _ := http.NewRequest("GET", url, nil)

req.Header.Add("x-wallet-id", "<x-wallet-id>")
    req.Header.Add("x-api-key", "NEYNAR_API_DOCS")

res, _ := http.DefaultClient.Do(req)

defer res.Body.Close()
    body, _ := io.ReadAll(res.Body)

fmt.Println(string(body))
}

HttpResponse<String> response = Unirest.get("https://api.neynar.com/v2/farcaster/user/fid/")
  .header("x-wallet-id", "<x-wallet-id>")
  .header("x-api-key", "NEYNAR_API_DOCS")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.neynar.com/v2/farcaster/user/fid/")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Get.new(url)
request["x-wallet-id"] = '<x-wallet-id>'
request["x-api-key"] = 'NEYNAR_API_DOCS'

response = http.request(request)
puts response.read_body

Responses

Success Response

200

{
  "fid": 3
}

Error Responses

500

{
  "message": "<string>",
  "code": "<string>",
  "property": "<string>",
  "status": 123
}

Understanding Wallet ID for FID Operations

This endpoint fetches a fresh FID (Farcaster ID) that can be assigned to a new user. When you fetch a FID, Neynar maintains a “shelf” of pre-registered FIDs that are replenished asynchronously via onchain transactions.

Wallet ID (REQUIRED)

The x-wallet-id header is required for this endpoint. You must provide a wallet_id to cover the costs of async FID shelf replenishment.

Code Examples

• Node.js

const response = await fetch('https://api.neynar.com/v2/farcaster/user/fid', {
  headers: {
    'x-api-key': 'YOUR_NEYNAR_API_KEY',
    'x-wallet-id': 'your-wallet-id'  // REQUIRED
  }
});

const data = await response.json();
console.log('Fresh FID:', data.fid);
// Use this FID within 10 minutes to register an account

• cURL

curl -X GET 'https://api.neynar.com/v2/farcaster/user/fid' \
  -H 'x-api-key: YOUR_NEYNAR_API_KEY' \
  -H 'x-wallet-id: your-wallet-id'

• Python

import requests

headers = {
    'x-api-key': 'YOUR_NEYNAR_API_KEY',
    'x-wallet-id': 'your-wallet-id'  # REQUIRED
}

response = requests.get(
    'https://api.neynar.com/v2/farcaster/user/fid',
    headers=headers
)

data = response.json()
print(f"Fresh FID: {data['fid']}")

Error Handling

Error: Missing Wallet ID

{
  "code": "RequiredField",
  "message": "x-wallet-id header is required"
}

Solution: Add the x-wallet-id header. See Managing Onchain Wallets for setup instructions.

Error: Invalid Wallet ID

{
  "code": "InvalidWalletId",
  "message": "The provided wallet_id is invalid or not found."
}

Solution: Verify your wallet_id in the Developer Portal or contact support.

Error: Insufficient Wallet Balance

{
  "code": "InsufficientFunds",
  "message": "Wallet does not have enough balance to complete this transaction."
}

Solution: Fund your wallet with more ETH on Optimism.

Important Notes

Cold Start (First Call Only): The first time you call this endpoint with a new wallet_id, it will take approximately 1 minute to complete as it pre-registers a few FID accounts. Subsequent calls will be fast (< 1 second). Make sure your wallet has $5+ ETH on Optimism before the first call.

Wallet Consistency Required: The same wallet_id used to fetch a FID must also be used when calling POST /v2/farcaster/user/ to register that account. Using different wallets will result in an error.

10 Minute Deadline: After fetching a FID, you must call the register account endpoint within 10 minutes. Otherwise, Neynar will assign this FID to another user.