# Polygon

**Canonical:** https://apis.io/providers/polygon/  
**Website:** https://polygon.io/  
**APIs profiled:** 12

Polygon (Polygon.io, rebranded as Massive in early 2026) provides real-time and historical market data APIs across US stocks, options, indices, forex, cryptocurrencies, and futures. Coverage is delivered through REST endpoints and WebSocket streams under a single api.polygon.io surface plus an S3 flat files product, with tiered subscription plans for retail developers and Business contracts for redistribution and exchange-licensed data.

## Kin Score — 71.6 / 100 (exemplar)

Scored 2026-08-20 under rubric 0.12.0. Trend: flat (+0.0 from 71.6).

| Facet | Score |
|---|---|
| Discoverability | 92.6 |
| Contract Quality | 71.5 |
| Governance | 43.2 |
| Contract Governance | 43.2 |
| Operational Transparency | 57.9 |
| Developer Ergonomics | 56.5 |
| Commercial Clarity | 77.6 |
| Access Clarity | 77.6 |

Regulatory layer — **Securities & Market Data**: 68.3 (matched via tags).

## Agent readiness — 53.8 (agent-native)

| Dimension | Value |
|---|---|
| Spec Presence | yes |
| Agentic Access | derived |
| Reversibility Documented | na |
| MCP Server | verified |
| Auth Clarity | yes |
| Idempotency | na |
| Error Semantics | documented |
| OpenAPI Examples | no |
| Rate Limit Signal | documented |
| Event Surface Described | derived |
| Agent Skills | derived |
| 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 (12)

- **Polygon WebSocket API** — Real-time streaming WebSocket clusters per asset class (stocks/options/indices/forex/crypto). Subscribers authenticate with an API key and subscribe to channels for trades, quot...
- **Polygon Aggregates API** — Crypto aggregate bars.
- **Polygon Books API** — Level-2 order book.
- **Polygon Contracts API** — Option contract reference data.
- **Polygon Conversion API** — Real-time currency conversion.
- **Polygon CorporateActions API** — Stock splits and dividends.
- **Polygon DailyBars API** — Daily open/close.
- **Polygon Markets API** — Markets, exchanges, holidays, and status.
- **Polygon News API** — Ticker news.
- **Polygon Quotes API** — FX quote endpoints.
- **Polygon Snapshots API** — Snapshot endpoints.
- **Polygon Tickers API** — Ticker reference and metadata.

## MCP servers (1)

- **Massive MCP server — remote https://mcp.massive.com (OAuth) + open-source mcp_massive (stdio)**

## Agentic access (1)

- **Polygon Agentic Access** — 175 operations

## Security (2)

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

## Plans (1)

- **Polygon Plans Pricing**

## Use cases (5)

- **Trading platform price feeds** — Power retail and institutional trading UIs with consolidated real-time quotes and bars.
- **Backtesting and research** — Pull decades of aggregated bars and tick data for systematic strategy research.
- **Risk and surveillance** — Stream live trades and quotes into compliance, surveillance, and risk engines.
- **Analytics dashboards** — Build market dashboards, terminals, and embedded charts across asset classes.
- **Quant pipelines** — Drive options Greeks, volatility surfaces, and FX hedging models with reliable feeds.

## Tags

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

---

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