API Research
Find and validate real, live data sources. No hardcoded data allowed.
Step 1: Search for APIs
bash
# Web search for APIs web_search "<topic> free API" web_search "<topic> public API documentation" web_search "<topic> real-time data API" web_search "<topic> JSON API no auth"
Step 2: Validate API Endpoints
Test each potential API:
bash
# Test endpoint directly curl -s "<api_endpoint>" | head -c 500 # Check response # ✅ Returns JSON with real data # ✅ No authentication required (or has free tier) # ✅ Response time < 5 seconds # ❌ Returns error or empty # ❌ Requires paid API key
Common Free Data Sources
Finance & Crypto
| API | Endpoint | Notes |
|---|---|---|
| DeFiLlama | https://api.llama.fi/v2/chains | TVL, yields, derivatives |
| CoinGecko | https://api.coingecko.com/api/v3/simple/price?ids=bitcoin&vs_currencies=usd | Prices, trending |
| Yahoo Finance | https://query1.finance.yahoo.com/v8/finance/chart/AAPL | Stocks (unofficial) |
| Exchange Rates | https://api.exchangerate.host/latest | Currency rates |
Weather & Environment
| API | Endpoint | Notes |
|---|---|---|
| Open-Meteo | https://api.open-meteo.com/v1/forecast?latitude=52&longitude=13¤t_weather=true | No key needed |
| wttr.in | https://wttr.in/London?format=j1 | Simple weather |
| NOAA Space Weather | https://services.swpc.noaa.gov/products/noaa-scales.json | Space weather |
Geology & Space
| API | Endpoint | Notes |
|---|---|---|
| USGS Earthquakes | https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/significant_week.geojson | Real-time |
| NASA APOD | https://api.nasa.gov/planetary/apod?api_key=DEMO_KEY | Demo key works |
| ISS Location | http://api.open-notify.org/iss-now.json | Real-time position |
General Purpose
| API | Endpoint | Notes |
|---|---|---|
| IP Geolocation | http://ip-api.com/json/ | IP info |
| Countries | https://restcountries.com/v3.1/all | Country data |
| Universities | http://universities.hipolabs.com/search?country=united+states | School data |
| Random User | https://randomuser.me/api/ | Test data |
| Quotes | https://api.quotable.io/random | Random quotes |
| Jokes | https://v2.jokeapi.dev/joke/Any | Random jokes |
| Books | https://openlibrary.org/search.json?q=lord+of+the+rings | Book data |
| Wikipedia | https://en.wikipedia.org/api/rest_v1/page/summary/Claude_(AI) | Summaries |
| GitHub | https://api.github.com/users/langoustine69 | User/repo data |
Sports & Entertainment
| API | Endpoint | Notes |
|---|---|---|
| ESPN | https://site.api.espn.com/apis/site/v2/sports/football/nfl/scoreboard | Live scores |
| OMDB | https://www.omdbapi.com/?t=inception&apikey=<free_key> | Movies (free key) |
Step 3: Design Endpoints
Based on validated APIs, design 6 endpoints:
| Endpoint | Type | Price | Data Source |
|---|---|---|---|
overview | Free | $0 | Quick summary for discovery |
lookup | Paid | $0.001 | Single item by ID/name |
search | Paid | $0.002 | Filtered list query |
top | Paid | $0.002 | Rankings/leaderboards |
compare | Paid | $0.003 | Multi-item comparison |
report | Paid | $0.005 | Comprehensive analysis |
Output
Provide:
- •Validated API endpoints (tested, working)
- •6 endpoint designs with descriptions
- •Data mapping (which API feeds which endpoint)
Red Flags
- •❌ API requires paid key with no free tier
- •❌ Rate limits too strict (< 100 req/day)
- •❌ Data is stale (not updated regularly)
- •❌ Endpoint returns HTML instead of JSON
- •❌ Requires OAuth/complex auth flow
Next Step
→ Use lucid-agents-sdk skill to create the agent code