Polygon.io

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.

Polygon.io publishes 8 APIs on the APIs.io network, including Stocks API, Options API, Indices API, and 5 more. Tagged areas include Fintech, Market Data, Stocks, Options, and Forex.

The Polygon.io catalog on APIs.io includes 1 event-driven AsyncAPI specification and 1 Spectral governance ruleset.

Polygon.io’s developer surface includes authentication, developer portal, documentation, pricing, GitHub presence, and 7 more developer resources.

🌐 Visit website 📡 Source on GitHub

36.7/100 thin ▬ flat Agent 24/100 agent aware saas Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0

AccessFreemiumSelf serve⚡ Free to try

1 APIs

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

Kin Score

Kin Score How this is scored →
scored 2026-09-08 · rubric v0.20.0

Composite quality — 36.7/100 · thin

Contract Quality 12.8 / 21

Developer Ergonomics 5.3 / 17

Access Clarity 4.5 / 17

Operational Transparency 2.3 / 11

Contract Governance 1.2 / 10

Discoverability 5.8 / 9

Regulatory Posture 4.5 / 15

Agent readiness — 24/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 6 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 9 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 7 / 7

Typed Event Surface 6 / 6

Agent Skills 0 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 4 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Regulatory Posture applies to this provider. Its tags matched the Securities & Market Data regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

Create-or-Update Ergonomics does not apply to this provider. The published contracts declare no write operations, and a read-only API cannot create-or-update. The facet is excluded from this provider's denominator entirely — not scored zero. A reference or data API is not deficient for being unable to upsert.

The six quality facets above are damped to 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from github.com/api-evangelist/polygon-io: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

APIs 8

Individual APIs this provider publishes, each with its own machine-readable definition.

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.

Scroll for all 8

Open Collections 4

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

API Collection

OPEN COLLECTION

Polygon.io REST API (Stocks) Aggregates API

OPEN COLLECTION

Polygon.io REST API (Stocks) Aggregates Reference API

OPEN COLLECTION

Polygon.io REST API (Stocks)

OPEN COLLECTION

Pricing Plans 1

Published pricing tiers and plan structures.

Polygon Io Plans Pricing

5 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Polygon Io Rate Limits

4 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals for API financial operations.

Polygon Io Finops

FINOPS

Event Specifications 1

AsyncAPI definitions for this provider's event-driven and streaming APIs.

Polygon.io WebSocket APIs

Streaming WebSocket APIs from Polygon.io (now operating as Massive) for real-time and delayed US Stocks, Options, Forex, Crypto, Indices, and Futures market data. Clients connec...

ASYNCAPI

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Polygon.io API Rules

9 rules · 1 errors 8 warnings

SPECTRAL

Security Posture 2

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Polygon Io Authentication

apiKey/http · 2 schemes

SECURITY

Polygon Io Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Polygon Io Agentic Access

3 operations

3 operations · 0 acting

AGENTIC

Resources

Get Started 1

Portal, sign-up, and the first successful call

Portal

Portal

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

Build 1

SDKs, sample code, and the tooling you integrate with

GitHub

GitHub

Access & Security 2

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Authentication

Authentication

Operate 2

Status, limits, changes, and where to get help

StatusPage

StatusPage

RateLimits

RateLimits

Commercial 3

Pricing, plans, and the legal terms of use

Pricing

Pricing

Plans

Plans

FinOps

FinOps

Company 1

The organization behind the API

LinkedIn

Source (apis.yml)

aid: polygon-io
url: https://raw.githubusercontent.com/api-evangelist/polygon-io/refs/heads/main/apis.yml
name: Polygon.io
kind: company
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: true
  label: Hosted service · you call their endpoint
  confidence: high
  source:
  - openapi
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: freemium
  onboarding: self-serve
  trial: false
  try_now: true
  public: false
  label: Freemium · Self-serve signup
  confidence: medium
  source:
  - plans
  - authentication
  - security
  - url: https://polygon.io/
    status: 301
    note: declared website redirects to https://massive.com/ — a different registrable domain (polygon.io -> massive.com),
      possible rename or acquisition (probed 2026-09-03, roadmap#169)
  generated: '2026-09-03'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/polygon-io.png
tags:
- Fintech
- Market Data
- Stocks
- Options
- Forex
- Crypto
- Indices
- Futures
- WebSockets
- Real-Time
- Historical
tags_raw:
- Fintech
- Market Data
- Stocks
- Options
- Forex
- Crypto
- Indices
- Futures
- WebSockets
- Real-time
- Historical
created: '2026-05-08'
modified: '2026-05-29'
specificationVersion: '0.23'
description: 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.
apis:
- aid: polygon-io:stocks-api
  name: Polygon.io Stocks API
  tags:
  - Stocks
  - Equities
  - Market Data
  - Real-Time
  tags_raw:
  - Stocks
  - Equities
  - Market Data
  - Real-time
  image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
  baseURL: https://api.polygon.io
  humanURL: https://polygon.io/docs/stocks
  description: Real-time and historical US equity market data including aggregates (minute/hour/day bars), trades, NBBO quotes,
    snapshots, ticker reference, splits, dividends, and financials. Available via REST and WebSocket.
  properties:
  - type: Documentation
    url: https://polygon.io/docs/stocks
  - type: AsyncAPI
    url: asyncapi/polygon-io-asyncapi.yml
  x-features:
  - Real-time and historical aggregates
  - NBBO trades and quotes
  - Snapshots and ticker reference
  - Corporate actions
  - WebSocket streaming
  x-use-cases:
  - Power equity charts and tickers
  - Backtest strategies on historical bars
  - Stream live trades into surveillance systems
- aid: polygon-io:options-api
  name: Polygon.io Options API
  tags:
  - Options
  - OPRA
  - Market Data
  image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
  baseURL: https://api.polygon.io
  humanURL: https://polygon.io/docs/options
  description: 'OPRA-licensed options market data via REST and WebSocket: aggregates, trades, quotes, snapshots, contract
    reference, and option chains.'
  properties:
  - type: Documentation
    url: https://polygon.io/docs/options
  - type: AsyncAPI
    url: asyncapi/polygon-io-asyncapi.yml
  x-features:
  - OPRA-licensed options data
  - Snapshot and chain endpoints
  - Greeks and IV (paid tiers)
  - WebSocket streaming
  x-use-cases:
  - Options trading research
  - Volatility surface modeling
  - Greeks dashboards
- aid: polygon-io:indices-api
  name: Polygon.io Indices API
  tags:
  - Indices
  - Market Data
  image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
  baseURL: https://api.polygon.io
  humanURL: https://polygon.io/docs/indices
  description: Real-time and historical index values for major US and global indices via REST and WebSocket.
  properties:
  - type: Documentation
    url: https://polygon.io/docs/indices
  - type: AsyncAPI
    url: asyncapi/polygon-io-asyncapi.yml
  x-features:
  - Index values and aggregates
  - Snapshots
  - WebSocket streaming
  x-use-cases:
  - Benchmark performance tracking
  - Index-based product pricing
- aid: polygon-io:forex-api
  name: Polygon.io Forex API
  tags:
  - Forex
  - FX
  - Currency
  - Market Data
  tags_raw:
  - Forex
  - FX
  - Currencies
  - Market Data
  image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
  baseURL: https://api.polygon.io
  humanURL: https://polygon.io/docs/forex
  description: Real-time and historical FX prices for 1,000+ currency pairs via REST and WebSocket.
  properties:
  - type: Documentation
    url: https://polygon.io/docs/forex
  - type: AsyncAPI
    url: asyncapi/polygon-io-asyncapi.yml
  x-features:
  - 1,000+ currency pairs
  - Aggregates and quotes
  - WebSocket streaming
  x-use-cases:
  - Multi-currency reporting
  - FX trading strategies
- aid: polygon-io:crypto-api
  name: Polygon.io Crypto API
  tags:
  - Crypto
  - Cryptocurrency
  - Market Data
  image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
  baseURL: https://api.polygon.io
  humanURL: https://polygon.io/docs/crypto
  description: Aggregates, trades, snapshots, level-2 books, and L2 streaming for crypto pairs across major exchanges.
  properties:
  - type: Documentation
    url: https://polygon.io/docs/crypto
  - type: AsyncAPI
    url: asyncapi/polygon-io-asyncapi.yml
  x-features:
  - Aggregated cross-exchange data
  - Level-2 order books
  - WebSocket streaming
  x-use-cases:
  - Crypto trading and analytics
  - Cross-exchange arbitrage research
- aid: polygon-io:futures-api
  name: Polygon.io Futures API
  tags:
  - Futures
  - Market Data
  image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
  baseURL: https://api.polygon.io
  humanURL: https://polygon.io/docs/futures
  description: Real-time and historical futures market data including aggregates, trades, quotes, and snapshots.
  properties:
  - type: Documentation
    url: https://polygon.io/docs/futures
  - type: AsyncAPI
    url: asyncapi/polygon-io-asyncapi.yml
  x-features:
  - CME-licensed futures data
  - Aggregates and snapshots
  - Continuous contracts
  x-use-cases:
  - Futures trading research
  - Commodities and rates analytics
- aid: polygon-io:polygon-io-aggregates-api
  name: Polygon.io Aggregates API
  description: Aggregate (OHLC) bar data.
  humanURL: https://polygon.io/docs/stocks
  baseURL: https://api.polygon.io
  tags:
  - Aggregates
  properties:
  - type: OpenAPI
    url: openapi/polygon-io-aggregates-api-openapi.yml
- aid: polygon-io:polygon-io-reference-api
  name: Polygon.io Reference API
  description: Ticker reference data.
  humanURL: https://polygon.io/docs/stocks
  baseURL: https://api.polygon.io
  tags:
  - Reference
  properties:
  - type: OpenAPI
    url: openapi/polygon-io-reference-api-openapi.yml
common:
- type: AgenticAccess
  url: agentic-access/polygon-io-agentic-access.yml
- type: DomainSecurity
  url: security/polygon-io-domain-security.yml
- type: Authentication
  url: authentication/polygon-io-authentication.yml
- type: LinkedIn
  url: https://www.linkedin.com/company/polygon-io
- type: Portal
  url: https://polygon.io/
- type: Documentation
  url: https://polygon.io/docs
- type: Pricing
  url: https://polygon.io/pricing
- type: StatusPage
  url: https://status.polygon.io/
- type: GitHub
  url: https://github.com/polygon-io
- type: Plans
  url: plans/polygon-io-plans-pricing.yml
- type: RateLimits
  url: rate-limits/polygon-io-rate-limits.yml
- type: FinOps
  url: finops/polygon-io-finops.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

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