API Research

Find and validate real, live data sources. No hardcoded data allowed.

Step 1: Search for APIs

# 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:

# 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&current_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:

1. Validated API endpoints (tested, working)
2. 6 endpoint designs with descriptions
3. 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