# Polygon.io

**Canonical:** https://apis.io/providers/polygon-io/  
**Website:** https://polygon.io/  
**APIs profiled:** 8

Polygon.io (rebranded as Massive in early 2026) provides real-time and historical market data APIs across stocks, options, indices, forex, crypto, and futures via REST, WebSocket streaming, and S3-style flat files. APIs cover trades, quotes, aggregates, snapshots, ticker reference data, and corporate actions.

## Kin Score — 37.8 / 100 (thin)

Scored 2026-08-20 under rubric 0.12.0. Trend: flat (+0.0 from 37.8).

| Facet | Score |
|---|---|
| Discoverability | 74.1 |
| Contract Quality | 62.3 |
| Governance | 11.4 |
| Contract Governance | 11.4 |
| Operational Transparency | 21.1 |
| Developer Ergonomics | 31.0 |
| Commercial Clarity | 26.3 |
| Access Clarity | 26.3 |

Regulatory layer — **Securities & Market Data**: 30.0 (matched via tags).

## Agent readiness — 36.2 (agent-ready)

| Dimension | Value |
|---|---|
| Spec Presence | yes |
| Agentic Access | derived |
| Reversibility Documented | na |
| MCP Server | no |
| Auth Clarity | yes |
| Idempotency | na |
| Error Semantics | no |
| OpenAPI Examples | no |
| Rate Limit Signal | documented |
| Event Surface Described | derived |
| Agent Skills | no |
| Well Known Catalog | no |
| Consent Identity | no |
| Agent Card | no |
| Dry Run Mode | na |

## Access

Freemium · Self-serve signup — onboarding: self-serve, pricing: freemium, trial: no (confidence: high).

## APIs (8)

- **Polygon.io Stocks API** — Real-time and historical US equity market data including aggregates (minute/hour/day bars), trades, NBBO quotes, snapshots, ticker reference, splits, dividends, and financials. ...
- **Polygon.io Options API** — OPRA-licensed options market data via REST and WebSocket: aggregates, trades, quotes, snapshots, contract reference, and option chains.
- **Polygon.io Indices API** — Real-time and historical index values for major US and global indices via REST and WebSocket.
- **Polygon.io Forex API** — Real-time and historical FX prices for 1,000+ currency pairs via REST and WebSocket.
- **Polygon.io Crypto API** — Aggregates, trades, snapshots, level-2 books, and L2 streaming for crypto pairs across major exchanges.
- **Polygon.io Futures API** — Real-time and historical futures market data including aggregates, trades, quotes, and snapshots.
- **Polygon.io Aggregates API** — Aggregate (OHLC) bar data.
- **Polygon.io Reference API** — Ticker reference data.

## Agentic access (1)

- **Polygon Io Agentic Access** — 3 operations

## Security (2)

- **Polygon Io Authentication** — apiKey/http · 2 schemes
- **Polygon Io Domain Security** — TLSv1.3 · HSTS · DMARC

## Plans (1)

- **Polygon Io Plans Pricing**

## Tags

Fintech, Market Data, Stocks, Options, Forex, Crypto, Indices, Futures, WebSockets, Real-Time, Historical

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/polygon-io/). Scores are computed from the provider's own public artifacts under a published rubric.