Tony Wang4 min readBest Financial Data API for AI Agents: Stocks, Crypto, SEC, Predictions
Not a real-time trading feed. Compare financial data APIs for AI agents needing stocks, crypto, SEC filings, and prediction markets in one key.
Search "best financial data API for developers" and you'll land on Polygon.io, Alpha Vantage, Finnhub, Twelve Data, and similar vendors — companies whose entire pitch is licensed, low-latency market data for trading systems. This guide is not a claim to compete with them on that. It's for a different job: an AI agent, a research tool, or a side-project that needs stock and crypto snapshots, SEC filings, and prediction-market data from one place, without wiring up four separate vendors and API keys for each.
What the real-time specialists do better
Credit where it's due, because this matters for choosing correctly:
- Licensed, low-latency feeds. Polygon.io and Databento sell direct exchange data with real millisecond-level guarantees — not something a public-page API replicates.
- Deep historical tick data. Backtesting a trading strategy needs years of tick-by-tick history; that's a specialist product, priced and engineered for it.
- SLAs and support built for production trading. If a feed going down costs you money in real time, you want a vendor whose business is that guarantee.
If any of that is your actual requirement, stop here and pick a specialist. The rest of this guide is for everyone else.
What to look for in a broader financial data API
- What's the actual use case — an execution system (needs a real-time specialist), or an agent/research tool that reads snapshots and filings (a broader API fits)?
- Does it cover the specific source you need — equities, crypto, SEC filings, prediction markets — or only one?
- For SEC data specifically: does it expose full-text search and insider/institutional filings, or only basic company lookup?
- Pricing model: per-seat subscription for a fixed data source, or usage-based across multiple sources?
- A free tier to test the actual fields you need before committing.
The landscape
| Category | Examples | What you get | Fit |
|---|---|---|---|
| Real-time market data | Polygon.io, Databento, Twelve Data | Licensed, low-latency feeds, deep tick history | Trading systems, backtesting |
| General stock APIs | Alpha Vantage, Finnhub, EODHD | Fundamentals, historical prices, company data | Dashboards, single-source apps |
| Crawlora | — | Stock/crypto snapshots, SEC EDGAR filings (full-text search, insider, institutional), prediction markets — one key, credit-based | AI agents, research tools, multi-source projects |
Where Crawlora is genuinely differentiated: SEC EDGAR
Most financial-data APIs stop at price and fundamentals. Crawlora's SEC platform covers the filings layer most of them don't:
Full-text search across every EDGAR filing — several incumbents gate this behind a paid tier; Crawlora exposes it directly:
curl -s "https://api.crawlora.net/api/v1/sec/full-text-search" \
-H "x-api-key: $CRAWLORA_API_KEY" \
--data-urlencode "q=\"supply chain disruption\"" \
--data-urlencode "forms=10-K,10-Q" \
--data-urlencode "from=2026-01-01"
Parsed insider transactions from Form 3/4/5 filings — who at a company bought or sold, and when:
curl -s "https://api.crawlora.net/api/v1/sec/insider?ticker=AAPL&limit=10" \
-H "x-api-key: $CRAWLORA_API_KEY"
13F institutional holdings — what a fund manager holds, sorted by value:
curl -s "https://api.crawlora.net/api/v1/sec/institutional-holdings?cik=0001067983&limit=50" \
-H "x-api-key: $CRAWLORA_API_KEY"
Building an agent that reasons about a company — earnings sentiment, who's buying or selling, who's holding — this is the layer a pure price API doesn't reach.
The rest of the coverage
- Yahoo Finance and Google Finance — ticker quotes, historical OHLCV, financials, analyst ratings, dividends, splits, and options chains as normalized JSON. Snapshot data from public pages, not a licensed real-time feed.
- CoinGecko — crypto market rows, global charts, trending coins. Documented as public market data, not intended for trading execution.
- Kalshi and Polymarket — prediction-market data most financial APIs don't cover at all, useful as an alternative demand signal alongside price and filing data.
When to use a real-time specialist instead
- You're executing trades and a stale price costs real money.
- You need tick-level historical data for backtesting.
- Your product is single-source (just equities, or just crypto) and a dedicated vendor's deeper feature set beats broader coverage.
Stocks, crypto, SEC filings, and prediction markets in one key
Credit-based pricing across every source, 2,000 free credits a month, no card.
Related reading
- Google Finance API Guide — the Google Finance endpoint in depth.
- How to Scrape Yahoo Finance — ticker history, financials, and options data.
- How to Scrape CoinGecko — crypto market data in detail.
Frequently asked questions
Is Crawlora a real-time market data API?
No. Crawlora's stock and crypto endpoints return public-page snapshot data, not licensed real-time feeds. For trading systems that need millisecond-level guarantees, use a specialist like Polygon.io or Databento.
What makes Crawlora's SEC data different from other financial APIs?
Most financial data APIs cover price and fundamentals but not the filings layer. Crawlora exposes full-text search across every EDGAR filing (which several incumbents gate behind paid tiers), parsed insider transactions from Form 3/4/5 filings, and 13F institutional holdings.
Does Crawlora cover cryptocurrency data?
Yes, via the CoinGecko endpoint — market rows, global charts, and trending coins. It's documented as public market data intended for research, not order execution.
What are prediction markets, and why would I need that data?
Kalshi and Polymarket let people trade on real-world event outcomes; their market prices reflect aggregated probability estimates. Few financial data APIs cover this source, making it a distinct signal alongside price and filing data.
Who is this API actually for?
AI agents, research tools, and fintech side-projects that need breadth across stocks, crypto, SEC filings, and prediction markets under one API key and credit system — not production trading systems that need a real-time licensed feed.