Best stock market data API for developers

Combined ranking

1. 1
   MMassive—18 pts

   GPT #1Claude #1Gemini #1Grok #3

   Best overall developer package for U.S. equities: clean REST/WebSocket APIs, full-market coverage, trades, quotes, aggregates, reference data, corporate actions, financials, snapshots, and flat files with generous paid-tier limits.

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   GPT Best overall developer package for U.S. equities: clean REST/WebSocket APIs, full-market coverage, trades, quotes, aggregates, reference data, corporate actions, financials, snapshots, and flat files with generous paid-tier limits.

   Claude The default choice for serious individual developers and small teams — direct SIP-sourced US equities/options/indices data, flat-fee unlimited API calls, excellent WebSocket streaming, clean docs and official client libraries, and flat-file (S3) bulk historical access; absorbed much of IEX Cloud's user base after its 2024 shutdown and has kept improving.

   Gemini Exceptional latency, comprehensive tick-level historical and real-time market data, robust WebSocket streaming, and top-tier developer documentation make it the premier choice for production applications. Assumes high data fidelity and low latency are prioritized.

   Grok Leading low-latency real-time US equities/options data with WebSockets, tick-level history, high reliability/uptime, and strong dev infrastructure for trading/charting apps; excels where speed and US depth matter most.

   Where it falls short

   per GPT Global exchange coverage and commercial redistribution rights require additional products or agreements.

   per Claude US-centric — thin international equity coverage, and real-time (vs 15-min delayed) tiers get expensive fast once you need full SIP feeds or options at scale.

   per Gemini Premium tiers for real-time streaming and full historical tick data are costly, making it expensive for early-stage side projects.

2. 2
   DDatabento—8 pts

   GPT #2Claude #2Gemini —Grok —

   Highest-fidelity choice for quantitative and trading systems, with direct-feed data, nanosecond timestamps, L2/L3 order books, historical replay, normalized schemas, and unusually transparent licensing; a near-tie with Massive when data quality matters more than simplicity.

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   GPT Highest-fidelity choice for quantitative and trading systems, with direct-feed data, nanosecond timestamps, L2/L3 order books, historical replay, normalized schemas, and unusually transparent licensing; a near-tie with Massive when data quality matters more than simplicity.

   Claude Best raw data quality available to ordinary developers — normalized direct-from-venue feeds (CME, Nasdaq, OPRA, etc.) with nanosecond timestamps, full order-book depth (MBO), transparent usage-based pricing with no license negotiation, and a strong Python/Rust/C++ client stack; ranked assuming the practitioner cares about research/backtesting fidelity, where nothing else at this price tier comes close.

   Where it falls short

   per GPT Its pricing, exchange concepts, and data volumes are excessive for ordinary dashboards or lightweight applications.

   per Claude Not a casual REST lookup service — pay-per-byte pricing punishes exploratory "give me everything" queries, no fundamentals/news, and the L3/binary-format model is overkill if you just need daily closes.

3. 3
   TTwelve Data—7 pts

   GPT #3Claude —Gemini #3Grok #5

   Strongest global general-purpose option, combining broad international equities coverage, fundamentals, technical indicators, REST, and WebSockets behind an approachable API.

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   GPT Strongest global general-purpose option, combining broad international equities coverage, fundamentals, technical indicators, REST, and WebSockets behind an approachable API.

   Gemini Delivers outstanding global exchange coverage across stocks, forex, and crypto with clean REST/WebSocket interfaces and multi-language SDK support. Near-tie with Financial Modeling Prep for general versatility. Assumes international equity coverage is required.

   Grok Reliable global multi-asset coverage, clean time-series, good uptime, spreadsheet integrations, and flexible pricing/credits suitable for dashboards and mid-scale apps; practical value for consistent multi-market access.

   Where it falls short

   per GPT Credit-based limits become complicated and expensive for large symbol universes or high-frequency collection.

   per Gemini High-frequency WebSocket concurrency and deep historical tick granularity are gated behind higher monthly subscription tiers.

4. 4
   AAlpaca Market Data—6 pts

   GPT #4Claude —Gemini #2Grok —

   Seamlessly unifies market data feeds with commission-free algorithmic trade execution APIs, offering developer-first SDKs and smooth paper-to-live trading transitions. Assumes the practitioner is building automated execution workflows or trading bots.

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   Gemini Seamlessly unifies market data feeds with commission-free algorithmic trade execution APIs, offering developer-first SDKs and smooth paper-to-live trading transitions. Assumes the practitioner is building automated execution workflows or trading bots.

   GPT Excellent value for developers building U.S. trading applications, with polished SDKs, streaming data, stocks, options, crypto, paper trading, and seamless execution integration.

   Where it falls short

   per GPT The free feed is IEX-only and recent full-market data requires the paid plan; historical depth is comparatively short.

   per Gemini Full market depth features require paid subscriptions, and global coverage outside US equities and crypto is limited.

5. 5
   AAlpha Vantage▲36 pts

   GPT —Claude —Gemini #5Grok #1

   Broadest balanced coverage (stocks, ETFs, options, forex, crypto, commodities, fundamentals, technical indicators, macro) with strong developer experience, technical indicators built-in, NASDAQ licensing for compliance, excellent free tier for prototyping, AI/MCP readiness, and reliable for algo trading/research/dashboards without stitching providers; top-rated overall for typical developers in 2026 reviews.

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   Grok Broadest balanced coverage (stocks, ETFs, options, forex, crypto, commodities, fundamentals, technical indicators, macro) with strong developer experience, technical indicators built-in, NASDAQ licensing for compliance, excellent free tier for prototyping, AI/MCP readiness, and reliable for algo trading/research/dashboards without stitching providers; top-rated overall for typical developers in 2026 reviews.

   Gemini High accessibility with an extensive suite of built-in technical indicators, historical intraday feeds, and widespread SDK/library support for rapid prototyping. Assumes low-volume or indie developer usage patterns.

   Where it falls short

   per Gemini Strict request rate limits and occasional latency spikes render lower tiers inadequate for high-throughput production environments.

6. 6
   FFinancial Modeling Prep—5 pts

   GPT —Claude #5Gemini #4Grok #4

   Offers unmatched coverage for deep company fundamentals, financial statements, SEC filings, and valuation metrics alongside core pricing feeds. Assumes fundamental analysis is central to the application.

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   Gemini Offers unmatched coverage for deep company fundamentals, financial statements, SEC filings, and valuation metrics alongside core pricing feeds. Assumes fundamental analysis is central to the application.

   Grok Solid all-in-one with real-time prices, rich fundamentals/SEC filings, earnings, news, and good pricing for building complete apps; reliable uptime and developer-friendly for balanced indie/enterprise workflows.

   Claude The best fundamentals-first API for the money — 30+ years of standardized financial statements, ratios, DCF inputs, earnings call transcripts, and screeners alongside serviceable price data, at prices far below Intrinio or a Bloomberg/LSEG contract; ideal for stock-screener and valuation apps.

   Where it falls short

   per Claude Price/quote data is a secondary strength — latency and intraday quality lag Polygon/Databento, and standardization occasionally smooths over as-reported nuances that rigorous fundamental quants need.

   per Gemini Less suited for ultra-low latency real-time WebSocket tick streaming compared to dedicated market data providers.

7. 7
   TTiingo▼24 pts

   GPT #5Claude #3Gemini —Grok —

   Outstanding value for end-of-day and IEX-sourced intraday US equity data — famously clean, survivorship-bias-aware historical prices back decades, generous cheap tiers (~$10–30/mo), plus news and crypto endpoints; the quiet favorite of quant hobbyists and backtesters.

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   Claude Outstanding value for end-of-day and IEX-sourced intraday US equity data — famously clean, survivorship-bias-aware historical prices back decades, generous cheap tiers (~$10–30/mo), plus news and crypto endpoints; the quiet favorite of quant hobbyists and backtesters.

   GPT Exceptional value for research and EOD workflows, offering clean adjusted history, broad securities coverage, long price histories, news, and predictable flat-rate individual pricing.

   Where it falls short

   per GPT Internal-use licensing and less mature consolidated real-time equities support make it unsuitable for many customer-facing live-data products.

   per Claude Intraday/real-time comes from IEX's exchange feed only (~2–3% of volume), so quotes can diverge from consolidated tape — not suitable for live trading signals; near-tie with Finnhub below.

8. 8
   EEODHDnew4 pts

   GPT —Claude —Gemini —Grok #2

   Exceptional global coverage (150k+ tickers, 60+ exchanges), deep historical data (30+ years), fundamentals, one-API simplicity, strong value pricing, and high scores across coverage/pricing/licensing for backtesting, screeners, and international apps; consistent high merit for production use.

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   Grok Exceptional global coverage (150k+ tickers, 60+ exchanges), deep historical data (30+ years), fundamentals, one-API simplicity, strong value pricing, and high scores across coverage/pricing/licensing for backtesting, screeners, and international apps; consistent high merit for production use.

9. 9
   FFinnhub▼22 pts

   GPT —Claude #4Gemini —Grok —

   Broadest free tier still standing in 2026 — real-time-ish US quotes, global equity coverage, plus fundamentals, earnings, insider transactions, and alternative data (sentiment, transcripts) under one API; excellent for prototyping and international breadth on a budget. Near-tie with Tiingo; Finnhub wins on breadth, Tiingo on price-history quality.

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   Claude Broadest free tier still standing in 2026 — real-time-ish US quotes, global equity coverage, plus fundamentals, earnings, insider transactions, and alternative data (sentiment, transcripts) under one API; excellent for prototyping and international breadth on a budget. Near-tie with Tiingo; Finnhub wins on breadth, Tiingo on price-history quality.

   Where it falls short

   per Claude Data quality and depth are uneven outside core US endpoints — fundamentals have gaps/errors at the margins, and rate limits on paid tiers are tighter than Polygon's.

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Tracked by ModelsAgree · rank 1 = 5 pts … rank 5 = 1 pt · re-polled weekly