Transport for Chicago, US API
Overview
The Chicago Transit Authority (CTA) API provides real-time train tracking and bus arrival predictions for Chicago's public transit network. An API key is required and can be requested for free from the CTA developer site. It is a solid choice for building transit apps focused on the Chicago metro area.
Beginner Tip
Request a free API key from the CTA developer portal and include it as the key parameter in every request. Start with the Train Tracker API using a known station stop ID such as 40380 (Chicago/Red Line).
Available Data
Example Response
{
"route": "Line 1",
"origin": "Station A",
"destination": "Station B",
"departure": "08:30",
"arrival": "09:15",
"status": "On Time",
"delays_min": 0
} Field Reference
ctatt.tmst Timestamp of when the API response was generated ctatt.errCd Error code; "0" means success ctatt.eta Array of upcoming train arrival predictions eta.staNm Name of the station for this arrival prediction eta.arrT Predicted arrival time in YYYYMMDD HH:mm:ss format eta.isDly Flag indicating if the train is delayed ("1" = delayed) Implementation Example
const url = "http://www.transitchicago.com/developers/";
// Replace headers or query params with the values required by this API.
const response = await fetch(url, {
headers: {
"X-API-Key": "YOUR_API_KEY"
}
});
if (!response.ok) throw new Error(`Request failed: ${response.status}`);
const data = await response.json();
console.log(data); What Can You Build?
Note: These code examples are AI-generated and unverified. Always refer to the official API documentation for accurate usage.
Common Errors & Troubleshooting
Matrix Score Breakdown
Partially tested on Apr 5, 2026
Technical Specifications
Related Tags
Similar APIs
View All →AIS Hub
AIS Hub aggregates real-time Automatic Identification System data from a global network of shore-based receivers to track marine vessels.
AZ511
AZ511 is the official Arizona Department of Transportation traffic data API providing real-time road conditions, incidents, and camera information for Arizona highways.
Bay Area Rapid Transit
⭐ Beginner's PickThe BART API provides real-time train arrival predictions, station information, and service advisories for the Bay Area Rapid Transit system in the San Francisco Bay Area.
BlaBlaCar
BlaBlaCar provides programmatic access to search car sharing trips via REST API.
Boston MBTA Transit
⭐ Beginner's PickThe Boston MBTA Transit API gives you real-time data for the Massachusetts Bay Transportation Authority, including train, bus, and ferry arrivals.