Free Financial Data API for AI

A financial data API for AI gives language models structured access to stock prices, fundamentals, and market data. Traditional REST APIs require authentication, rate-limit management, and response parsing. MCP (Model Context Protocol) replaces that plumbing with a direct database connection the model queries in English.

Shibui Finance is a free MCP server that takes a different approach from traditional providers. Instead of forwarding each request to a rate-limited REST API, it gives Claude and ChatGPT direct access to a pre-loaded database with 64 years of US stock market data: 31M+ daily prices, quarterly financials, daily valuations, and 56 technical indicators for 10,000+ companies. No API key, no per-request costs, fair-use limits only.

Most other MCP servers for financial data (Alpha Vantage, FMP, EODHD, Massive/Polygon) are API-forwarding: Claude sends a question, the server calls the provider's REST API, and returns whatever comes back. A screening query that checks 10,000+ stocks needs 10,000 API requests. With a pre-loaded database, that same query runs as a single SQL statement in seconds.

What people mean when they search for a financial data API

The search usually starts with a specific need: get historical stock prices into a model, pull quarterly earnings for a set of companies, or feed valuation data into an analysis pipeline. The expected solution is a REST API with JSON responses, authentication via API key, and some rate limit on a free tier.

That model works well for applications that need one data point at a time: a dashboard showing a single stock's price chart, a portfolio tracker refreshing positions, or a notification system watching a watchlist. These are request-response workflows. The application knows which ticker it wants before it asks.

AI workflows are different. When you ask Claude "find US stocks with P/E under 15 that grew revenue every year for five years," Claude does not know which tickers match until it has checked all of them. That is a cross-market scan, not a single-ticker lookup. Traditional APIs were not built for this.

Financial data API providers compared

These are the providers most commonly recommended for stock market data. Many now offer MCP servers alongside their REST APIs, so Claude can connect to them directly. But the MCP server matters less than what sits behind it: most wrap the same rate-limited API, while one pre-loads the data into a database.

Free tiers and entry prices as listed on each provider's pricing page on September 23, 2026 (USD, monthly billing unless noted; several are cheaper billed annually). They change often, so check the provider before you build on a free tier.

For a deeper comparison of Shibui vs specific providers, see Shibui vs Alpha Vantage MCP. The "MCP server" column matters because having one does not mean the rate limits go away. An API-forwarding MCP server translates the model's request into the same REST API calls you would make yourself. The rate limit, the API key requirement, and the per-request cost all carry through. It is a convenience wrapper, not a different data model.

Why APIs break down for AI workflows

Consider a simple question: "Which US stocks with a market cap above $5 billion have grown revenue every quarter for the last two years?" Whether Claude calls a REST API directly or uses an API-forwarding MCP server, it still needs to:

1. Fetch a list of all US stocks (1 request)
2. Filter by market cap (1 request per stock, or a screening endpoint if available)
3. Fetch 8 quarterly revenue figures per remaining stock (8 requests each)
4. Compare quarters sequentially to check for continuous growth

Even with a generous API, that is thousands of requests. At 25 per day (Alpha Vantage free tier), the query would take months. At 60 per minute (Finnhub), it would still take over an hour and exhaust daily quotas. Most AI conversations expect answers in seconds.

Claude writes a single SQL query that joins the valuation and financials tables, filters by market cap, checks 8 consecutive quarters of revenue growth, and returns the results. One query, a few hundred milliseconds, no per-ticker API calls. The difference is not optimization. It is a different data model.

API-forwarding vs pre-loaded: the architecture that matters

Most financial data providers now offer MCP servers, which is the right direction. But having an MCP server does not solve the rate-limit problem if the server still makes one API call per data point behind the scenes. There are two architectures:

API-forwarding MCP (Alpha Vantage, FMP, EODHD, Massive (formerly Polygon), Twelve Data, Finnhub): the MCP server receives the model's request, translates it into REST API calls, and returns the results. The rate limits, API keys, and per-request costs all carry through. This is convenient (Claude connects directly instead of you writing code), but the screening bottleneck remains. A cross-market scan still hits the API thousands of times.

Pre-loaded database MCP (Shibui Finance): the data is already in a database. Claude writes SQL queries against it directly. No API call per request, no per-request quota, no per-query cost. A screening query that would require 10,000 API calls runs as a single database query in milliseconds.

With an API-forwarding MCP server, that comparison still requires separate API calls for each metric, each company, each year. With Shibui, Claude writes one query joining the fundamentals and valuation tables. The model controls the SQL, so it can adapt the comparison to whatever you ask without hitting fixed endpoint structures. See the full MCP server comparison for a deeper breakdown.

REST API call vs. MCP query: side by side

Get AAPL's trailing P/E ratio and market cap. With a REST API, you need an API key, an HTTP request, and JSON parsing:

import requests

API_KEY = "your_key"
url = f"https://www.alphavantage.co/query?function=OVERVIEW&symbol=AAPL&apikey={API_KEY}"
resp = requests.get(url)
data = resp.json()
print(f"P/E: {data.get('TrailingPE')}, Market Cap: {data.get('MarketCapitalization')}")

That returns one company at a time. Comparing 5 companies means 5 separate calls. Adding quarterly revenue history means 5 more calls to a different endpoint with a different response format.

With MCP, you ask in English:

Claude writes a single SQL query joining the valuation and fundamentals tables, returns all 5 companies in one pass. No API key, no pagination, no response normalization. To try it yourself:

claude mcp add shibui-finance --transport streamable-http https://mcp.shibui.finance/mcp

Full setup walkthrough: How to Get Stock Data into Claude or How to Get Stock Data into ChatGPT.

What Shibui Finance covers

Shibui connects Claude to a single, pre-built database covering US equities on NYSE and NASDAQ:

• Daily prices: 31M+ rows back to 1962, OHLCV for 10,000+ symbols
• Quarterly and yearly financials: income statements, balance sheets, cash flow
• Daily valuations: P/E, P/B, market cap, enterprise value, PEG ratio (daily history back to 1993)
• Derived metrics: EV/EBITDA, P/S, FCF yield, dividend yield, earnings yield
• Technical indicators: 56 indicators including RSI, MACD, Bollinger Bands, moving averages, ADX, candlestick patterns
• SEC filings: 6.4M filing records back to 1993, every form type, updated daily
• Insider transactions: Forms 3, 4, 5 + Schedule 13D/13G with cluster-buying signal flags
• Analyst estimates: Forward PEG, consensus earnings estimates

Data refreshes daily after market close. Setup takes about two minutes with the step-by-step guide, and requires no API key, no account, and no payment. For full schema details, see the data sources page. For screening, see the AI stock screener or browse the full feature list.

Once connected, you can automate queries on a schedule. The workflow guides show how to build daily screeners, portfolio monitors, and SEC filing alerts that run unattended.

That query touches four tables (stock_quotes, technical_indicators, fundamentals, valuation) and returns in under a second. With a traditional API, you would need separate calls for each data type for each of 10,000+ stocks.

When you still need a traditional API

Shibui is not a replacement for every financial data API. It serves a specific use case well (AI-driven analysis of US equities) and does not pretend to cover everything:

• Real-time or intraday data: Shibui is end-of-day only. If you need tick-level or streaming data, Massive (formerly Polygon.io) or Twelve Data are built for that.
• International markets: Shibui covers US equities (NYSE, NASDAQ). For global coverage across 60+ exchanges, EODHD or Finnhub are stronger options.
• Options, crypto, forex: Not in Shibui's database. Alpha Vantage and Massive (formerly Polygon) cover these.
• Programmatic scheduled access: Shibui does support scheduled workflows through Claude Code and MCP-compatible agents (see replacing yfinance with MCP), but if you need a traditional REST endpoint for a non-AI pipeline, use a REST API directly.
• Custom application backends: Shibui has no REST endpoint. If you are building a web application that needs to serve financial data to a frontend, use a traditional API.

The honest positioning: Shibui is built for one thing - AI assistants analyzing US equity data across companies and time periods. It does that well. It is not a general-purpose financial data API.

Frequently asked questions

Is there a free financial data API with no rate limits?

Shibui Finance is free, needs no API key and has no per-request quotas. Fair-use limits apply to stop bulk scraping; a typical research session stays well under them. It connects Claude to a pre-loaded database of 64 years of US equity data via MCP, so a market-wide screen is one query rather than thousands of API calls. Alpha Vantage offers a free tier limited to 25 requests per day. Financial Modeling Prep and EODHD also have restricted free tiers.

Which financial data providers have a free tier?

Most do, with tight limits. Alpha Vantage allows 25 requests per day, Financial Modeling Prep 250 per day, EODHD 20 per day, Twelve Data 800 per day (8 per minute), Finnhub 60 per minute, and Massive (formerly Polygon.io) 5 per minute for end-of-day data. Nasdaq Data Link offers free datasets, and Intrinio has a free trial only. Shibui Finance is free with no API key and fair-use limits, and because it pre-loads 64 years of US equity data, a full-market screen is one query instead of thousands of API calls.

What is the best free stock data API for AI?

For AI assistants like Claude, an MCP server outperforms a traditional API. Shibui Finance connects Claude to a pre-loaded financial database: no API keys, no per-request quotas (fair-use limits only), and the model writes SQL directly instead of making thousands of individual HTTP requests. For programmatic access outside of AI, Alpha Vantage and Financial Modeling Prep both offer free tiers with broad coverage.

Can Claude access financial data without an API key?

Yes. Shibui Finance requires no API key, no account registration, and no configuration beyond a one-click connection. It gives Claude read access to 10,000+ US equities with 64 years of daily prices, quarterly financials, daily valuations, and 56 technical indicators. Setup takes about two minutes.

What is MCP and how does it compare to a REST API?

MCP (Model Context Protocol) is a standard for connecting AI models to external data sources. Where a REST API returns one response per HTTP request, MCP gives the model direct access to query a database. For financial analysis, this means Claude can screen 10,000+ stocks in a single query instead of making 10,000 API calls. MCP is to AI what REST was to web applications: the native protocol for the platform.

Does Shibui Finance have a REST API?

No. Shibui Finance is an MCP server, not a REST API. It connects directly to Claude and other AI assistants that support MCP. The model writes SQL queries against the database and gets structured results back. If you need a traditional REST API for a dashboard or application, Alpha Vantage, Financial Modeling Prep, or Massive (formerly Polygon) are better options.

What financial data providers work with Claude?

Several providers now offer MCP servers for Claude: Shibui Finance (pre-loaded US equity database, free), Alpha Vantage (API-forwarding MCP, free tier with limits), Financial Modeling Prep (API-forwarding MCP, free tier with limits), EODHD (API-forwarding MCP, 20 calls/day free), and Intrinio (API-forwarding MCP, paid plans only). Nasdaq Data Link now has an official MCP server too. Shibui is the only one that pre-loads the data, meaning queries run against the database directly with no external API call per request. See the full comparison.