Massive (formerly Polygon.io) review
Broad market data with REST, streaming, and bulk downloads for developer-built finance products.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
Massive (formerly Polygon.io) provides financial market data for developers building trading applications, analytics tools, and other financial products. Its coverage spans stocks, options, futures, indices, forex, crypto, and economics, with additional alternative data described by the vendor. Developers can request data through REST endpoints, stream market updates over WebSockets, or download historical flat files for bulk analysis. This breadth suits teams that want several market-data types through one API-oriented service; it is less suited to buyers seeking a single-purpose finance dataset.
The access options matter for different workloads. REST endpoints support on-demand queries, while WebSockets are intended for live market updates. Historical data is available through API endpoints and flat-file downloads, giving applications and research workflows distinct ways to retrieve it. Official client libraries are available for Python, Go, Kotlin/JVM, and JavaScript. The listed integrations include Claude Code, Claude Desktop, Cursor, ChatGPT, Codex, GitHub Copilot, and Gemini CLI. This developer-centered mix is a fit for teams building in supported languages and workflows, though buyers should check that their preferred language and data needs align before choosing.
According to the vendor's pricing page, Stocks Basic costs $0 per month and includes 5 API calls per minute, 2 years of historical data, end-of-day data, and reference data. Stocks Starter is $29 monthly, with unlimited API calls, 5 years of history, and 15-minute delayed data; Stocks Developer is $79 monthly and extends history to 10 years. Stocks Advanced costs $199 monthly, with 20+ years of history and real-time data. These are individual Stocks plans, while business pricing differs. Massive is a strong fit when broad coverage and multiple delivery methods are priorities; teams needing real-time stock data should look at Advanced rather than the delayed-data tiers.
Massive (formerly Polygon.io) pros and cons
- Where it wins
- Covers stocks, options, futures, indices, forex, crypto, and economics
- Offers REST, WebSocket streaming, and historical flat-file downloads
- Stocks Basic is free; paid Stocks plans start at $29 per month
- Where it doesn't
- Stocks Basic is limited to 5 API calls per minute
- Stocks Starter and Developer provide 15-minute delayed data
- Plan prices shown apply to individual Stocks plans, not business plans
Massive (formerly Polygon.io) fact sheet, pricing and score →
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