Polygon.io beginner's guide — what it is, how it works, when to use it
With any new API, the hardest part is figuring out what it actually does and where it's useful. Let's start there.
What is Polygon.io?
Real-time market data for NASDAQ, NYSE and options — industry standard for algo trading.
Polygon.io is best-known in the algo trading community — real-time data, 20y of history, full options support. Free tier is 5 rpm and end-of-day only. Real-time plans run $29–$199/month.
Who it's for
- Algo traders
- Finance-AI developers
- Market research
A first example
Here is the shortest path to seeing something work:
curl "https://api.polygon.io/v2/aggs/ticker/AAPL/prev?apiKey=YOUR_KEY"When to use it, when not to
Polygon.io is a great fit for most of what it covers, but not every case. If you only need small, static data once or twice, it may be simpler to download and cache locally. For real products that need fresh data, the API is the way.