The API most people's first script talks to — free key, wide coverage, hard rate limits.
$50/mofree tier
Market Data APIs
Quote, bar, tick and fundamentals APIs for people who write their own code — compared on latency, history depth, free-tier limits and redistribution rights.
Six terms decide almost every choice in this category, and vendors describe all six inconsistently. They are normalised here so the comparison table means something.
Latency. Real-time means an exchange feed. Delayed usually means fifteen minutes. End-of-day means a daily bar after the close. A provider calling a fifteen-minute quote "live" is not lying by its own definitions, which is exactly why the field is normalised.
Source. Direct from an exchange, consolidated from the SIP, resold from another vendor, or aggregated from public pages. This is what determines whether full tick history exists at all, and it predicts price better than any tier name.
History depth. Usually shorter than the marketing page implies, and usually shortest on the cheap tier. Intraday history is the field that disappoints most often.
Free-tier limits. Normalised to requests per minute and per day, because "generous free tier" is not a unit.
Redistribution. Whether you may show the data to your own users. Separately priced or forbidden outright, and the most common licensing surprise in the category.
Delivery. REST, WebSocket, flat files. If you intend to backfill years of ticks, flat files are not a nice-to-have — paginating through that volume over REST is a project of its own.
Compare all 3
Generated from the category schema — every card fills in the same fields.
| Tool | From | Free tier | Data source | Delivery | History depth | Free tier limits | Entry paid tier, $/mo | Redistribution |
|---|---|---|---|---|---|---|---|---|
| Alpha Vantage | $50/mo | Yes | Aggregator | REST | 20+ years of daily bars; intraday history is shorter and varies by symbol | 25 requests/day, 5 requests/min | $50 | Prohibited |
| Polygon.io | $29/mo | Yes | Direct exchange | REST, Websocket, Flat files | Up to 20 years of trades and quotes on Advanced; 2 years on Starter | 5 requests/min, end-of-day data only, no WebSocket | $29 | Paid addon |
| yfinance | Free | Yes | Scraped | Library | Decades of daily bars; intraday limited to roughly 60 days | No published limit — Yahoo throttles by IP and the threshold is undocumented | No paid tier | Prohibited |
All tools
Full-tick US equities, options and forex from a direct exchange feed.
$29/mofree tier
The Python library everyone starts with — free, unofficial, and not something to build on.
Freefree tier
Head to head
FAQ
What is the cheapest real-time US market data API?
Real-time equity data generally starts around $29-50 a month. Anything advertised as free is delayed or end-of-day, whatever the marketing copy says — exchanges charge for real-time and nobody absorbs that cost for you.
Which market data APIs cover non-US markets?
Fewer than you would expect. Most US-focused providers are US-only at every tier, so the `non_us_markets` field is worth checking before price — no subscription level fixes missing coverage.
Can I show API data to my own users?
Usually not on a standard plan. Redistribution is a separate right, priced separately or forbidden outright, and it is the single most common licensing surprise for people building consumer products. Every card here records it.