Best Financial Data APIs for Developers (2027): Tested and Compared

Almost everyone who builds something around stock data hits the same wall. The prototype works on day one and you feel pretty good about it. Then on day three your script prints an error message where Apple's closing price should be, because the free quota was gone before lunch.

This guide is about that moment, when a free key stops being enough and you have to choose something you can actually live with for a year or two. I've tried to keep it practical. For each provider you'll get what the free plan really allows, where the paid plans start, what the catches are, and who each one suits.

What "tested" means in this article

Let me be straight about the word in the title. In October 2026 I went through the official pricing pages and documentation of every provider below, then checked their limits against independent developer write ups. Where two sources disagreed on a number, I say so instead of picking the nicer one.

What I did not do is run a speed contest. Response time depends on where your server sits and which endpoint you call, so a latency number from me would only mislead you. Near the end there's a simple way to measure it yourself in about an hour, and that result will matter more than anything I could print here.

Prices and limits in this space change often. Treat every figure as a snapshot from October 2026 and confirm it on the provider's own page before you pay anyone.

Five questions to answer before you compare anything

Most bad choices happen because people compare price first. Answer these instead, and the shortlist writes itself.

What kind of data do you need? Prices and company fundamentals are different products. Some providers are great at one and thin at the other.

How fresh does it need to be? An end of day price is fine for a portfolio tracker and useless for an alert system. Real time data costs far more than delayed data almost everywhere.

How many requests will you make? A dashboard that refreshes twenty tickers every ten seconds makes 120 calls a minute. That alone rules out several free plans.

Are you allowed to show this data to other people? This is the question developers skip, and it causes the most trouble later. More on it below.

What happens if this company disappears? It's not a silly question. IEX Cloud, which a lot of developers relied on, shut down on August 31, 2024 (source), and plenty of dashboards and bots went dark overnight. Whatever you pick, keep the provider behind a small layer in your own code so swapping it means changing one file instead of fifty.

The price and market data providers

Alpha Vantage

Official pages: Premium plans and pricing and free key and limits. Independent check of the 25 requests a day limit: Macroption.

Alpha Vantage is probably the first API most tutorials teach, so it's worth knowing what the free key looks like today. It allows 25 requests per day and 5 per minute. It used to be 500 a day, then 100, and now 25. On the free key, daily history is also limited to the most recent 100 data points, and real time or 15 minute delayed US market data is reserved for premium keys.

Twenty five requests sounds like a lot until you count. One call per ticker means a 25 stock watchlist is finished in a single refresh. For learning, or for a script that runs once a day on a handful of symbols, it's fine. For anything that runs on a schedule, it isn't.

The paid plans are priced by speed, not by volume. They start at 49.99 dollars a month for 75 requests per minute and climb to 249.99 dollars a month for 1,200 per minute, and none of them has a daily cap. Annual billing works out to about ten months of payments for twelve. The data is broad, with stocks, forex, crypto, fundamentals and more than fifty technical indicators, and it has an MCP server for AI tools. It's a good teacher and a modest production choice.

Massive, the company formerly known as Polygon.io

Official pages: Massive pricing. Rebrand announcement: Polygon.io is now Massive.

If you've seen tutorials that mention Polygon.io, this is the same company. It renamed itself Massive on October 30, 2025. Existing keys and accounts kept working, the old api.polygon.io address stays supported for an extended period, and a new api.massive.com address runs alongside it. The one thing that can bite you is the client libraries, which were renamed, so older code that imports the polygon package needs updating.

On the US stock side the individual plans are free, 29, 79 and 199 dollars a month. The free plan gives 5 calls a minute with end of day data. Paid plans list unlimited calls, but here's the detail that matters. The 29 and 79 dollar plans give you data delayed by 15 minutes. Real time US stock data starts at the 199 dollar Advanced plan. Those prices are for individual, non professional use, and business use is priced separately.

Developers consistently praise Massive for clean documentation and a well designed API, and it goes deep on US data, including tick level trades and quotes, options, indices, forex and futures. If you're building something price driven and American, it deserves a hard look. If you mostly need company fundamentals, it's not where I'd start.

Finnhub

Official page: Finnhub pricing. Independent comparison from a developer who ran four free APIs for two weeks: orthogonal.info.

Finnhub's free plan is the most generous one in this group for live data. You get 60 calls a minute, real time US quotes, a WebSocket stream for live prices, company news, basic fundamentals, forex and crypto, with no credit card. One developer who ran four free APIs side by side for two weeks on a small server found Finnhub the easiest to experiment with because he could refresh thirty tickers in under a minute with room to spare. He also noted some quirks in the data, such as pre market volume, so check what you receive before trusting it.

The catch is licensing. The free plan is for personal, non commercial projects. Once your app earns money, you're on a paid plan. Third party trackers put entry level paid plans at roughly 50 dollars a month, with premium data such as institutional fundamentals, global exchanges and tick data sold as separate add ons. That means two people on a premium plan can pay very different amounts, so get a quote from Finnhub itself before you plan a budget.

Twelve Data

Official pages: Pricing and how API credits and limits work.

Twelve Data's free Basic plan gives 8 API credits per minute and 800 per day, plus a small allowance of WebSocket credits. The word credits matters here. Some requests cost more than one credit depending on the data you ask for, so 800 credits does not always mean 800 calls.

Above the free plan, the page lists annual prices. The first paid plan, aimed at personal use with no daily limit, is 948 dollars a year, which works out to about 79 a month. The next one up, which adds commercial usage and pre and post market data, is 2,748 dollars a year, about 229 a month. The top plan is 11,988 dollars a year with an uptime guarantee of 99.95 percent. It suits people who need WebSocket streaming and wide global coverage, and it's priced like a service for teams more than for hobbyists.

The fundamentals focused providers

If you're building a screener, a valuation tool or anything that reads income statements, balance sheets and ratios, this group matters more than the one above.

ROIC.ai

Official pages: Pricing, API overview and latest price endpoint docs.

If your project is about understanding companies and not about watching ticks, ROIC.ai is the one I'd put at the top of the list to test first. It's built around company fundamentals and the numbers calculated from them, which is probably why it's named after return on invested capital. You get stock prices, income statements, balance sheets, cash flow statements, valuation multiples and earnings call transcripts from one API, on more than 70 exchanges. The company says it covers more than 68,000 tickers. That figure comes from its own published material, so check it against the tickers you personally need, but the free plan covers every ticker, so checking costs nothing.

What sets it apart from most of the others is the ratios. Profitability, credit and debt, liquidity, working capital and yield ratios are already calculated and served ready to use. That includes ROIC itself, debt to EBITDA and the Altman Z score, which saves you from rebuilding the same formulas and then wondering why your number differs from someone else's. The API has more than 70 endpoints, an OpenAPI specification, examples in cURL, Python, JavaScript, Ruby and Go, and support for Excel and Google Sheets, so analysts who don't write code can use it too. There's also a status page, which is a small thing that tells you the team expects people to depend on it.

The free plan is the part that surprised me most. It's not a cut down demo with a handful of sample symbols. It covers all tickers and the core endpoints at 5 requests per minute, with 2 years of annual fundamentals and daily prices, 2 quarters of earnings calls, and no credit card. Compare that with a free Alpha Vantage key at 25 requests a day, and for a fundamentals project the difference is real, because you can load a whole watchlist slowly over a few minutes. Batch prices, exchange calendars and the earnings calendar need a paid plan.

The paid plans are simple. Individual is 29 dollars a month for 300 requests per minute and 5 years of history. Professional is 89 dollars a month with no request cap and 40 plus years of history, which is the plan that makes long term backtests and deep valuation history possible. Enterprise, at 599 dollars a month, adds commercial use, multiple users and invoicing. There are no add on bundles to decode, so you can predict your bill, which is not true of every provider on this list.

It also ships a hosted MCP server with 36 tools, so AI assistants such as Claude can query statements, ratios and transcripts directly instead of you writing glue code. If you're building anything with an AI layer on top of financial data, that saves days of work.

The honest limits, so nothing surprises you. It serves daily prices only. The latest price endpoint returns the most recent daily record and not an intraday tick, so it isn't for live trading screens. It has no options chain and no cryptocurrency data. And new fundamentals appear when a company files, not when it talks about earnings on a call, which is the correct approach but means a number can appear a little after the headline. For screeners, valuation tools, research dashboards, newsletters and AI research assistants, those limits rarely matter. For price streaming, pair it with something like Finnhub or Massive. ROIC.ai's own comparison pages with other providers are written by the company, so verify their claims against the other provider's current page.

Financial Modeling Prep

Official pages: FMP pricing plans and how to choose a plan. Price comparison used for the monthly figures: multiples.vc.

Financial Modeling Prep, usually called FMP, picked up a lot of developers when IEX Cloud closed. The free Basic plan allows 250 calls per day with end of day data and access to more than 150 endpoints. Be aware that many endpoints on the free plan are limited to a fixed set of symbols or aren't available at all, so test the exact endpoints you need before you plan around it.

The paid plans are Starter, Premium and Ultimate. They allow 300, 750 and 3,000 calls per minute. Prices have been quoted a little differently depending on the source and on whether you pay monthly or annually, with Starter somewhere around 19 to 22 dollars, Premium around 49 to 59 and Ultimate around 99 to 149 a month. Check the live page. Starter covers US markets only, higher plans add the UK and Canada, and global coverage plus transcripts arrive at the top tier. There's also a separate bandwidth limit over a rolling 30 days, which is 500 megabytes on free, 20 gigabytes on Starter, 50 on Premium and 150 on Ultimate. If you pull a lot of data, that second limit can surprise you before the call limit does.

FMP is a solid all rounder with deep history, as reported and standardized statements, and an MCP server. The free plan is a decent place to learn what the data looks like.

EODHD

Official page: EODHD pricing.

EODHD, formerly known as EOD Historical Data, sells by data product instead of by tier. The free plan gives 20 calls a day with one year of history. The paid packages are EOD Historical at 19.99 dollars a month, EOD plus Intraday at 29.99, Fundamentals at 59.99, and an All In One package at 99.99. Paid plans allow 100,000 calls a day and 1,000 per minute, which is a lot of room for the money.

The appeal is global coverage and long history at a low price, with more than 60 exchanges and 30 plus years of end of day data. The catch is that you have to pick the right package, because the cheapest one does not include fundamentals. Also, the All In One plan is for personal use. Startups and commercial products need a custom priced plan, so factor that in early.

The free official source most people forget

SEC EDGAR

Official page: SEC, Accessing EDGAR Data.

If you only care about US public companies, there's an official source that costs nothing. The SEC publishes company filings and the structured financial facts inside them through free APIs on data.sec.gov. You don't need a key. You do need to send a User-Agent header that identifies you, with a name and contact email, and requests without one are rejected with an error. The fair access limit is 10 requests per second.

The data is exactly what companies reported, in their own tagging, which makes it authoritative and also a little messy. Companies use different tags for similar things, and you'll spend real time cleaning it. Many developers use EDGAR as a free source of truth and a paid API for convenience. It covers US filers only, and it has no market prices.

The one to be careful with

yfinance

Sources: yfinance on PyPI and Scrapfly's guide to the Yahoo Finance API.

yfinance is a Python library that pulls data from Yahoo Finance, and it's everywhere in tutorials because it needs no signup and no key. But it isn't an official API. Yahoo shut its real public finance API in May 2017, and yfinance works by calling unofficial endpoints that Yahoo can change at any time. When that happens the library breaks until its maintainers catch up. You can also get rate limited for pulling too much.

The project's own documentation says it's intended for research and educational purposes and that Yahoo's data is for personal use. That's fine for a notebook, a class project or a quick analysis. It's the wrong foundation for a product other people pay for or depend on.

Free tiers side by side, in plain words

Finnhub gives the most room for live work, at 60 calls a minute with real time US quotes, but for personal use only. Twelve Data gives 800 credits a day at 8 a minute. FMP gives 250 calls a day. Alpha Vantage gives 25 a day. EODHD gives 20 a day. Massive and ROIC.ai both give 5 calls a minute, but they differ in what they hold, with Massive offering end of day US market data and ROIC.ai offering worldwide fundamentals and prices.

If you live somewhere where paying a foreign company by card is a headache, which is true for developers in a number of countries, these free tiers matter more than the marketing suggests. All of the above let you build and test properly without paying first, so use that time to find out whether the data actually fits your project.

The licensing trap

This is the part I'd read twice. A free or cheap plan very often comes with a personal use license. Finnhub's free plan is non commercial. Massive's individual plans are for non professional use. Twelve Data's first paid plan is for personal use and commercial use starts a tier higher. EODHD's packages are personal use and commercial products need a custom plan. yfinance sits on Yahoo's personal use terms. FMP's free plan comes with a personal license. ROIC.ai puts commercial use in its Enterprise tier.

None of this is unusual. Exchanges charge data vendors for the right to distribute prices, and vendors pass that on. But it means that the moment your side project gets users, ads or customers, your cheap plan may no longer cover what you're doing. Read the terms of any plan before you put its data in front of the public, and ask the provider in writing if the wording is unclear.

Which one should you pick

If you're learning or building a side project, start with Finnhub for live style prices or FMP for fundamentals. Both let you do real work without paying.

If you need real time US prices in a serious product, Massive's Advanced plan is the first individual tier that delivers it, and the price reflects that.

If you're building a screener, valuation tool or research dashboard, start with ROIC.ai. The free plan covers every ticker, and the ratios come pre calculated, so you can see within an afternoon whether it has what you need. Then compare it with FMP and EODHD on your own tickers, and use EDGAR to double check any number that looks odd.

If you want global coverage on a small budget, ROIC.ai, EODHD and Twelve Data are the ones to test. ROIC.ai is the easiest to try first because its free plan includes worldwide coverage. Run your actual exchanges through each of them.

If you're connecting an AI assistant, several providers now ship MCP servers, including ROIC.ai, Alpha Vantage, FMP, Massive and EODHD, and EDGAR has community built ones. Remember that on a free plan every tool call spends a request, so one chatty conversation can use up a small daily quota.

If you're building a commercial product, skip the cheapest plan in your comparison and go straight to asking about commercial licensing. It will save you a painful migration later.

How to run your own test in an hour

Pick two or three providers from your shortlist and make a free key for each. Write down the ten tickers you actually care about, including at least two that are not American if your project needs them. Then do the same four things with each provider.

Fetch the last price and the last two years of daily prices for those tickers, and compare the closing prices with a source you trust, such as the exchange or the company's own investor page. Fetch one income statement and one set of ratios for each, and compare revenue and net income with the company's latest filing. Time each request a few dozen times from the machine where your code will really run, and note the slowest ones as well as the average. Finally, deliberately go over the rate limit once and see how the error looks, since you'll need to handle it properly in your code.

Mismatched numbers, missing tickers and confusing errors show up in this exercise within the first hour, and they're far cheaper to find now than after launch.

Common mistakes to avoid

Choosing on price alone is the big one. A cheap plan that lacks the endpoint you need costs more than an expensive one that has it.

Calling the API on every page view is another. Cache what doesn't change quickly. Fundamentals change four times a year, so there's no reason to fetch them every minute.

Trusting a single source for important numbers is risky too. Providers standardize statements differently, so two APIs can report slightly different figures for the same company and both can be defensible.

And finally, hardcoding one provider everywhere. Keep a thin layer between your app and the API so you can switch when prices, terms or even the company itself change.

The short version

There's no single best financial data API, only the one that matches your data type, freshness needs, request volume and license. If your work is about company fundamentals, ROIC.ai is the best place to start. Whatever you choose, start free, test with your own tickers, read the licensing terms before you launch, and keep your code ready to switch. Do that and the provider you pick will matter a lot less than you fear.

Figures in this article were checked against provider pages and independent sources in October 2026. Please verify current pricing and limits on each provider's website before you subscribe.