Polygon.io.
Developer-first US market data, from flat-file history to real-time websockets.
Overview
Polygon delivers US equities, options, indices, and futures data through consistent REST and websocket APIs plus S3-style flat files for bulk history — the format quant research pipelines actually want. Tiered pricing spans hobbyist to institutional licensing, which lets a strategy graduate from prototype to production without a data-stack rewrite.
Where it fits
- Research pipelines that need clean bulk history (flat files) and the same vendor for live feeds.
- Developers replacing scraped or free data with licensed, supportable feeds.
- Options-strategy research requiring full-chain historical data at reasonable cost.
Constraints to weigh
- US-market focus; global coverage requires a second vendor.
- Entitlement rules (delayed vs real-time, display vs non-display) require reading the licensing terms carefully.
- Not a substitute for exchange-depth institutional feeds in latency-sensitive contexts.
In an agentic workflow
Deterministic pipelines — like the QISAgent daily snapshot — upgrade naturally from free data to Polygon's licensed endpoints: same rules, supportable inputs. That input-integrity step is itself a governance control (see data-integrity checks in the oversight framework).
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This profile is an independent editorial description; verify current pricing, licensing, and capabilities directly with the provider. Not affiliated with or endorsed by Polygon.io.