10 Best Free Market Data API for Algo Traders (My Go-To Picks)

Alright, letโs get real for a second. When I first started algo trading, I was on a tight budget. I needed good data, but I didnโt want to spend hundreds (or thousands) of dollars on expensive APIs. Sound familiar?
The good news is, there are plenty of free or affordable market data APIs out there that wonโt break the bank. The bad news? Not all of them are worth your time. So, Iโve done the legwork for you and put together a list ofย 10 genuinely free or low-cost API for Algo Tradersย that Iโve personally used or tested. Letโs dive in.
1. Alpha Vantage

Letโs start with a classic. Alpha Vantage is my go-to for stock and forex data. Itโs free, easy to use, and offers both historical and real-time data. The documentation is clear, and Iโve never had trouble integrating it into my projects. If youโre new to algo trading, this is a great place to start.
ย 2. Mobula API

Mobula is a fantastic alternative for crypto traders. It offers real-time market data, historical prices, and even wallet tracking for over 15,000 cryptocurrencies. The free tier is generous, with 300,000 credits per month and no rate limits. Iโve used it for building crypto bots, and itโs been a game-changer.
3. CoinMarketCap API

If youโre into crypto, CoinMarketCap is a solid alternative. It offers real-time and historical data on thousands of cryptocurrencies, including prices, market capitalization, and trading volume. The free tier is limited, but itโs perfect for developers and traders who need comprehensive market data without paying a premium.
4. Yahoo Finance

Okay, I know what youโre thinking: โYahoo Finance? Really?โ But hear me out. Itโs free, itโs reliable, and it covers a ton of assetsโstocks, ETFs, forex, you name it. Iโve used it for quick data pulls when I didnโt need anything fancy. Itโs not perfect, but it gets the job done.
5. Tiingo

Tiingo is one of those hidden gems I stumbled on a while back. Itโs got a mix of stock, forex, and crypto data, and I love that it includes news sentiment analysis. The free tier is a bit limited, but itโs worth checking out if you want something a little more advanced.
6. IEX Cloud

IEX Cloud is my top pick for US stock data. Itโs fast, reliable, and the free tier is surprisingly generous. Plus, itโs backed by IEX, the exchange that made waves with Flash Boys. If youโre trading US equities, this is a no-brainer.
7. Quandl (Nasdaq Data Link)


Quandl is like a treasure chest of financial data. Itโs got everything from stock prices to economic indicators. Some datasets are paid, but thereโs still plenty of free data to play with. Iโve used it for niche projects, and itโs always delivered.
8. Polygon (formerly Polygon.io)

Polygon is a beast when it comes to stock and options data. The free tier is limited, but if youโre serious about real-time data, itโs worth a look. Iโve used it for building high-frequency trading models, and itโs been rock-solid.
9. Financial Modeling Prep

If youโre into fundamental analysis like I am, Financial Modeling Prep is a game-changer. It offers free access to financial statements, analyst estimates, and more. Iโve used it for building valuation models, and itโs been incredibly useful.
10. OpenBB (formerly Gamestonk Terminal)

Last but not least, OpenBB is an open-source platform that aggregates data from multiple sources. Itโs not a traditional API, but I love how flexible it is. Iโve used it for experimenting with different datasets, and itโs been a huge time-saver.
The Catch with Free APIs
Now, letโs be real: free APIs arenโt perfect. Iโve run into rate limits, data delays, and missing features more times than I can count. But hereโs the thingโtheyโre a fantastic starting point. They let you test your ideas, refine your strategy, and learn the ropes without spending a dime.
And when youโre ready to scale up, you can always upgrade to a paid plan. But for now, these free tools are more than enough to get you started.
Whatโs Next?
If youย areย serious about algo trading, you know that staying ahead of the curve is everything.
Once youย haveย your data sorted,ย itย isย timeย toย buildย smarter, faster, and more efficient algorithms. Want to take your trading to the next level?ย Haveย aย look atย my blog on 10 AI Agent Tools That Are Reshaping the Algorithmic Trading Industry in 2025. It’sย filledย withย allย insights on how AI is revolutionizing tradingโtrust me, youย won’t want to missย it.