We built TerminalFeed entirely on free APIs. Every data feed you see on the dashboard, from real-time Bitcoin prices to earthquake alerts to the ISS tracker, runs on publicly available endpoints that cost us exactly zero dollars. Here is every single one we use, organized by category, with endpoints, rate limits, whether you need a key, and our honest take on each.

This is not a theoretical list. These are APIs we hit thousands of times a day in production. If something is listed here, it works.

> CRYPTO & FINANCE

Binance WebSocket Streams
Real-time crypto prices, order book depth, trade streams, and candlestick data via WebSocket.
Endpoint: wss://stream.binance.com:9443/ws/
Rate Limit: 5 connections per IP, 1024 streams per connection
Key Required: No
The best free source for live crypto price data. Period. Sub-second latency, rock solid uptime.
CoinGecko
Market data, coin metadata, historical prices, trending coins, exchange data, and global market stats.
Endpoint: api.coingecko.com/api/v3/
Rate Limit: 30 requests/min on the free tier
Key Required: No (for basic endpoints)
The most complete free crypto API available. Covers everything from prices to NFT floor data.
CoinCap
Real-time market data for 2,000+ cryptocurrencies via REST and WebSocket.
Endpoint: api.coincap.io/v2/assets
Rate Limit: 200 requests/min
Key Required: No
Clean, simple, and fast. Great alternative if CoinGecko rate limits are a problem.
Alternative.me (Fear & Greed Index)
Crypto Fear & Greed Index, historical values, and market sentiment data.
Endpoint: api.alternative.me/fng/
Rate Limit: Generous, no documented cap
Key Required: No
Simple and reliable. One endpoint, one purpose, always works.
Mempool.space
Bitcoin mempool data, fee estimates, block info, address lookups, and Lightning Network stats.
Endpoint: mempool.space/api/
Rate Limit: Generous for reasonable use
Key Required: No
The gold standard for Bitcoin network data. Nothing else comes close for mempool and fee analysis.
Frankfurter
Foreign exchange rates sourced from the European Central Bank. Supports 30+ currencies.
Endpoint: api.frankfurter.app/latest
Rate Limit: No documented limit
Key Required: No
Lightweight, fast, and backed by ECB data. Perfect for currency conversion widgets.

> NEWS & SOCIAL

Hacker News (Firebase API)
Top stories, new stories, best stories, comments, and user data from Hacker News.
Endpoint: hacker-news.firebaseio.com/v0/
Rate Limit: Firebase-level scalability
Key Required: No
Real-time and rock solid. Built on Firebase, so it handles any load you throw at it.
Reddit RSS/JSON
Subreddit feeds, post data, and comments in JSON format by appending .json to any subreddit URL.
Endpoint: reddit.com/r/{subreddit}/.json
Rate Limit: ~60 requests/min (unofficial)
Key Required: No
Rate limited and occasionally flaky, but it works for basic feed aggregation without OAuth.
Bluesky (AT Protocol)
Public social data, user profiles, posts, and feeds from the Bluesky network.
Endpoint: public.api.bsky.app
Rate Limit: 3,000 requests/5 min for public endpoints
Key Required: No (for public data)
Growing fast. The public API is generous and the data is interesting for trend analysis.

> WORLD DATA

USGS Earthquake Feeds
Global seismic data in GeoJSON format, updated every minute. Magnitude, location, depth, and tsunami alerts.
Endpoint: earthquake.usgs.gov/earthquakes/feed/v1.0/summary/
Rate Limit: No limit (static feeds updated every 60s)
Key Required: No
Updated every minute, perfectly structured, and extremely reliable. One of our favorite feeds.
Open-Meteo
Weather forecasts, historical weather data, air quality, marine, and climate data for any location on Earth.
Endpoint: api.open-meteo.com/v1/forecast
Rate Limit: 10,000 requests/day free
Key Required: No
The best free weather API, period. No key, generous limits, global coverage, and excellent docs.
GDACS (Global Disaster Alerting)
Global disaster alerts covering earthquakes, floods, tropical cyclones, droughts, and volcanic activity.
Endpoint: gdacs.org/xml/rss.xml (RSS feed)
Rate Limit: No limit
Key Required: No
Covers natural disasters globally. RSS format is old school but the data is invaluable.
Seismic Portal (EMSC)
European seismic data with a real-time WebSocket stream for earthquake events worldwide.
Endpoint: seismicportal.eu (WebSocket + REST)
Rate Limit: No documented limit
Key Required: No
The WebSocket stream is great for real-time earthquake monitoring alongside USGS data.
NASA APOD
Astronomy Picture of the Day. High-resolution space imagery with expert explanations, updated daily.
Endpoint: api.nasa.gov/planetary/apod
Rate Limit: 1,000 requests/hr
Key Required: Yes (free, takes 30 seconds to get)
Beautiful daily content. The free API key signup is instant. Worth it for any dashboard or app.

> DEV & TECH

GitHub API
Repository data, trending repos, user profiles, commit history, issues, and pull requests.
Endpoint: api.github.com
Rate Limit: 60 req/hr unauthenticated, 5,000 req/hr with token
Key Required: No (but recommended)
Essential. The 60 req/hr unauthenticated limit is tight, so generate a personal access token.
Stack Exchange API
Questions, answers, tags, users, and trending content from Stack Overflow and the entire SE network.
Endpoint: api.stackexchange.com/2.3/
Rate Limit: 300 req/day without key, 10,000 with free key
Key Required: No (but helps significantly)
Good for surfacing trending questions and popular tags. The free key is worth the 2 minutes.
Statuspage APIs
Service status for major platforms (GitHub, Cloudflare, Discord, Vercel, etc.) via their public status pages.
Endpoint: {service}.statuspage.io/api/v2/status.json
Rate Limit: No documented limit
Key Required: No
Useful for monitoring dashboards. Most major services expose this. Just find their status URL.

> SPACE

Open Notify
Current ISS position (latitude/longitude) and the number of astronauts currently in space.
Endpoint: api.open-notify.org/iss-now.json
Rate Limit: No documented limit
Key Required: No
Fun and simple. Two endpoints, both return clean JSON. Great for starter projects.
The Space Devs (Launch Library 2)
Rocket launches (upcoming and historical), space events, astronaut bios, and space station data.
Endpoint: ll.thespacedevs.com/2.3.0/
Rate Limit: 15 req/hr on free tier
Key Required: No
The most comprehensive launch data available. The 15 req/hr limit means you need to cache aggressively.

> SECURITY

URLhaus (abuse.ch)
Database of malware distribution URLs, payloads, and threat indicators maintained by the community.
Endpoint: urlhaus-api.abuse.ch/v1/
Rate Limit: No documented limit
Key Required: No
Essential for security monitoring. The data quality is excellent and it updates constantly.
ThreatFox (abuse.ch)
Indicators of Compromise (IOCs) database covering malware, C2 servers, and threat intelligence feeds.
Endpoint: threatfox-api.abuse.ch/api/v1/
Rate Limit: No documented limit
Key Required: No
Solid threat intel feed. Pairs well with URLhaus for a complete picture of active threats.
CISA KEV (Known Exploited Vulnerabilities)
The official US government catalog of vulnerabilities that are actively being exploited in the wild.
Endpoint: cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json
Rate Limit: No limit (static JSON file)
Key Required: No
Official US government source. If a CVE is on this list, it is being exploited right now. Take it seriously.

> PREDICTION MARKETS

Polymarket (Gamma API)
Prediction market data including active markets, odds, volume, and resolution criteria.
Endpoint: gamma-api.polymarket.com
Rate Limit: Generous for reasonable use
Key Required: No
Fascinating data source. Real money on the line makes these odds more honest than polls.

> ENTERTAINMENT

SteamSpy
Steam game statistics including player counts, ownership estimates, playtime, and genre tags.
Endpoint: steamspy.com/api.php
Rate Limit: ~4 req/sec
Key Required: No
Fun data for gaming dashboards. Player count trends are surprisingly addictive to watch.
Dog CEO
Random dog images by breed, sub-breed listings, and breed-specific photo galleries.
Endpoint: dog.ceo/api/breeds/image/random
Rate Limit: No limit
Key Required: No
Instant mood booster. We use it for our 404 page. Zero regrets.
The Cat API
Random cat images, breed info, and categorized cat photos. The feline equivalent of Dog CEO.
Endpoint: api.thecatapi.com/v1/images/search
Rate Limit: 10 req/min without key
Key Required: Free key available
Similar to Dog CEO but with breed data included. The free key removes rate limits entirely.

> REFERENCE

Wikimedia APIs
"On This Day" historical events, Wikipedia recent changes SSE stream, and page content APIs.
Endpoint: api.wikimedia.org + stream.wikimedia.org/v2/stream/recentchange
Rate Limit: Generous
Key Required: No
Wikipedia's live edit stream is mesmerizing. Watch the world update an encyclopedia in real time.
ZenQuotes
Random inspirational and motivational quotes with author attribution.
Endpoint: zenquotes.io/api/random
Rate Limit: 5 req/30 sec
Key Required: No
Good for dashboard widgets and loading screens. Simple, clean, and always available.

> One API to Rule Them All

Here is the thing: calling 30+ APIs individually is a pain. We know because we do it. That is why we built the TerminalFeed Briefing API, which aggregates all of these data sources into a single, clean JSON response.

One call to /api/briefing gives you crypto prices, fear and greed, earthquake data, ISS position, top Hacker News stories, weather, security alerts, and more. All normalized, all cached, all free.

Check out our Developer API docs to get started. No key required for basic access.

If you are building a dashboard, a Discord bot, an AI agent, or just want to play with real-time data, start there. You can always break out to the individual APIs listed above when you need more granular control.

Happy building.