Massive API
Institutional-grade real-time market data at sub-20ms latency
Freemium
✓ Verified
🇺🇸 United States
Massive, formerly known as Polygon.io, is the infrastructure choice for developers building financial applications that need low-latency, high-reliability market data. It covers all US exchanges (including dark pools and OTC), options, crypto, forex, and indices with data going back to 2003. WebSocket streaming provides real-time trade and quote feeds. At under 20ms latency, it’s used by algorithmic trading firms, fintech apps, and professional market analytics platforms. Paid plans start at $199/month — premium but worth it for production applications requiring data quality guarantees.
API Details
Auth Method
API Key
Pricing Model
Freemium
Free Tier
Yes — 5 requests/min (delayed data)
Rate Limit
Unlimited (Starter+)
Format
REST / WebSocket / JSON
Versioning
v2, v3
SLA / Uptime
99.9%
Compliance
SIA and FINRA data agreements
Geographic Restrictions
US markets (all exchanges), options, crypto, forex
Last Verified
2026-02-20
Categories
Frequently Asked Questions
Massive provides real-time and historical US stock, options, forex, and crypto data. It includes trades, quotes (NBBO), aggregates (OHLCV), reference data, and corporate actions. Massive is particularly strong for options data and tick-level historical data u2014 areas where competitors like Alpha Vantage are weaker.
Massive offers a free tier with delayed data and 5 API calls per minute. Paid plans: Starter ($29/month) for 15-minute delayed data, Developer ($79/month) for real-time data, Advanced ($199/month) for unlimited requests and WebSocket streaming. Options data requires the Advanced plan. Annual billing gives 2 months free.
Yes. Massive has a WebSocket API for real-time streaming of trades, quotes, and aggregate data. This is available on the Advanced plan and above. The WebSocket feed is suitable for algorithmic trading applications that need sub-second data delivery. REST polling for real-time applications is supported on all paid plans.
Massive is a fraction of the cost of Bloomberg Terminal ($24,000/year) or Refinitiv Eikon while covering the core data needs of most algorithmic trading and fintech applications. Bloomberg remains superior for research, news, and institutional-grade data depth. For startups and mid-size applications, Massive provides excellent value.