Callook.info — Free US Ham Radio Call Sign API (No Key)

TL;DR

Callook.info is a REST API that queries the FCC's amateur radio call sign database. Pass any US call sign (e.g., W1AW, KE0OG, N0CALL) and get back the licensee's name, address, license class (Technician, General, Extra), grant date, expiration date, and operating status. Returns clean JSON with no authentication. It is the go-to API for ham radio apps, repeater directories, and radio club membership tools.

Quick start: https://callook.info/KE0OG/json

No API key needed — data is public FCC records!

How to Use This API

1. Look Up a Call Sign

Replace KE0OG with any FCC-issued US call sign. The API returns data in JSON format:

https://callook.info/KE0OG/json

2. JavaScript — Search and Display

const callSign = document.getElementById('callsign').value;
fetch(`https://callook.info/${callSign}/json`)
  .then(r => r.json())
  .then(data => {
    console.log('Name:', data.name);
    console.log('Class:', data.operClass);
    console.log('Expires:', data.expDate);
    console.log('Address:', data.address.line2);
  })
  .catch(err => console.log('Call sign not found'));

3. Python — Batch Lookup

import requests

callsigns = ['W1AW', 'KE0OG', 'N0CALL']
for cs in callsigns:
    r = requests.get(f'https://callook.info/{cs}/json')
    if r.status_code == 200:
        d = r.json()
        print(f"{cs}: {d['name']} — {d['operClass']} — exp {d['expDate']}")
    else:
        print(f"{cs}: not found")

Try KE0OG: https://callook.info/KE0OG/json

Look Up KE0OG

Frequently Asked Questions

What license classes are returned?: The API returns Technician, General, Advanced, Extra, or Club based on the FCC database classification.
Does this work for Canadian or other non-US call signs?: No — Callook.info queries the FCC database which only covers US-issued licenses. For other countries, try the respective national regulator.
How current is the data?: The FCC database is synced regularly. New grants and renewals typically appear within a few days of issuance.
What fields are in the JSON response?: Current: name, callsign, operClass, status, grantDate, expDate, address (line1, line2, attention). Also includes previous callsign if applicable.
Is there a rate limit?: No documented rate limit. The service has been stable for years and is widely used in the amateur radio community.
Can I look up a person by name instead of call sign?: The REST API only supports call sign lookup. For name-based searches, use the FCC's ULS system directly.

API Details

API URL: https://callook.info/
Documentation: https://callook.info/api/
Category: Data
Authentication: Not Required
Geographic Coverage: United States — FCC-issued amateur radio licenses

What You Can Build

Amateur radio repeater directory with owner information
Radio club membership roster verification tool
License expiration reminder app for ham operators
Field day participant lookup for contest logging
QRZ-style mobile call sign reference application