Free Timezone API for Developers: WorldClock.lol API Guide (2026)

WorldClock.lol offers a free JSON API for timezone data. No API key, no sign-up, no rate limits. CORS enabled for browser usage. Get current time for any city, compare timezones, search cities, and find meeting windows.

How Do I Get the Current Time for a City?

Make a GET request with a city slug:

GET https://www.worldclock.lol/api/v1/time?city=tokyo

Response:

{
  "city": "Tokyo",
  "country": "Japan",
  "timezone": "Asia/Tokyo",
  "currentTime": "2026-02-27T14:30:00+09:00",
  "utcOffset": "+09:00",
  "abbreviation": "JST",
  "isDST": false,
  "localTime": "02:30:00 PM",
  "localDate": "Thursday, February 27, 2026",
  "unixTimestamp": 1772170200
}

How Do I Query by IANA Timezone?

GET https://www.worldclock.lol/api/v1/time?timezone=America/Los_Angeles

Returns the same format as city lookups, using any valid IANA timezone identifier.

How Do I Compare Two Cities?

GET https://www.worldclock.lol/api/v1/time?compare=new-york,london

Returns both cities' time data plus:

• timeDifference — hours, minutes, and a human-readable description
• businessHoursOverlap — how many hours of 9-5 overlap exist
• bestMeetingTimes — suggested meeting windows in both cities' local time

How Do I Search for Cities?

GET https://www.worldclock.lol/api/v1/cities?q=japan
GET https://www.worldclock.lol/api/v1/cities?country=india
GET https://www.worldclock.lol/api/v1/cities?timezone=Asia/Tokyo
GET https://www.worldclock.lol/api/v1/cities?q=new&limit=10

Returns matching cities with their IDs, timezones, population, and direct links.

What Are the Most Common City Slugs?

• new-york, london, tokyo, paris, sydney
• dubai, singapore, los-angeles, san-francisco
• chicago, berlin, mumbai, bangalore, seoul
• shanghai, hong-kong, toronto, sao-paulo

Full list of 1800+ cities: City Directory

JavaScript Example

// Fetch current time in Tokyo
const response = await fetch('https://www.worldclock.lol/api/v1/time?city=tokyo');
const data = await response.json();
console.log(`Time in ${data.city}: ${data.localTime}`);
// "Time in Tokyo: 02:30:00 PM"

// Compare two cities
const compare = await fetch('https://www.worldclock.lol/api/v1/time?compare=new-york,london');
const result = await compare.json();
console.log(result.timeDifference.description);
// "London is 5 hours ahead of New York"

Python Example

import requests

# Get time in a city
data = requests.get('https://www.worldclock.lol/api/v1/time?city=tokyo').json()
print(f"Time in {data['city']}: {data['localTime']}")

# Compare two cities
compare = requests.get('https://www.worldclock.lol/api/v1/time?compare=new-york,london').json()
print(compare['timeDifference']['description'])

Is There an OpenAPI Spec?

Yes. The full OpenAPI 3.1 spec is available at:

https://www.worldclock.lol/openapi.json

This allows API clients, code generators, and AI agents to auto-discover and integrate with the API.

Is There an MCP Server for AI Agents?

Yes. WorldClock.lol provides an MCP (Model Context Protocol) server that lets Claude and other AI agents use timezone tools natively. Add to your Claude Desktop config:

{
  "mcpServers": {
    "worldclock": {
      "command": "npx",
      "args": ["worldclock-mcp-server"]
    }
  }
}