Agentifact assessment — independently scored, not sponsored. Last verified Mar 6, 2026.
Polygon.io
Real-time and historical market data API covering stocks, options, forex, and crypto with WebSocket streaming
Solid choice for most workflows
You need reliable real-time and historical market data across stocks, options, forex, and crypto for building trading bots or financial dashboards without broker dependencies.
Excellent data quality and low-latency streaming on paid tiers ($29–$199+/mo); free tier limits to 5 calls/min and 2 years/50k points—upgrade for production volume.
Broker APIs like Alpaca or TradeStation impose rate limits, funding minimums, or inconsistent access that disrupt your agent pipelines.
Consistent uptime and quality matching brokers but with fees; WebSockets shine for live feeds, though costs scale with advanced features.
Free Tier Severely Restricted
Only 5 calls/min, 2 years historical or 50k points max—insufficient for production or backtesting beyond prototyping.
Polygon is pricier but offers dedicated reliability without broker ties; Alpaca free for unfunded accounts.
Need consistent multi-asset data, WebSockets, or avoid broker dependencies.
Budget-constrained with basic US stock needs and can tolerate potential limits.
Paid Tiers Required for Scale
Free tier throttles quickly; monitor usage as Developer/Starter plans ($29–$79/mo) are needed for real apps—set budgets to avoid surprise bills.
Trust Breakdown
What It Actually Does
Polygon.io gives developers APIs to fetch real-time and historical data on stocks, options, forex, and crypto markets. Product managers can use it to build apps that track prices, trades, and market snapshots for financial analysis.[2][3]
Real-time and historical market data API covering stocks, options, forex, and crypto with WebSocket streaming.
Fit Assessment
Best for
- ✓data-analysis
- ✓financial-data
Not ideal for
- ✗rate limit under burst load above 100 RPM
Known Failure Modes
- rate limit under burst load above 100 RPM
Score Breakdown
Protocol Support
Capabilities
Governance
- permission-scoping
- resource-limits
- audit-log