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 corporat
Polygon.io is an API provider whose private shares are listed on 1 secondary market: Nasdaq Private Market.
Polygon.io publishes 1 API indexed on the APIs.io network.
Where It Trades
Listing data is compiled from the public marketplace pages of Forge Global, Hiive, EquityZen, Nasdaq Private Market, and Augment. A listing indicates that a venue has published a page for this company — it is not an offer, a quote, or investment advice, and APIs.io has no affiliation with any venue.
Work with this as data
Every listing here is available over the APIs.io API and to AI agents over MCP. Secondary Market is not yet its own endpoint on the v1 API. Reach it through catalog search and the tag graph, or the MCP server.