# Caplight

> Caplight Technologies is a private-markets data and trading platform for institutional investors,
> covering 50,000+ VC-backed private companies with secondary-market pricing, a live institutional order
> book, trade and order history, funding rounds, investor participation, SEC-derived fund marks, COI
> filings, comparables and composite indices. Its MarketPrice(TM) estimate is implied from live bids,
> asks and closed secondary trades. Two machine surfaces: a versioned REST API (26 read-only GET
> operations, api_key header, public OpenAPI 3.1.0) and a hosted OAuth-protected MCP server for Claude.

Generated by API Evangelist from the Caplight public surface on 2026-08-09. Caplight publishes no
llms.txt of its own (GET https://www.caplight.com/llms.txt and https://platform.caplight.com/llms.txt
both miss). This file is an independent third-party index, not a Caplight document.

## APIs

- [Caplight REST API](https://platform.caplight.com/api/documentation.html): Versioned REST over the
  full dataset. v1 = company, MarketPrice, order book, trades, fund marks, COIs, news, stock splits,
  quarterly summaries. v2 = company lookup and details, funding rounds, investors, comps, composite
  index. Base URL https://us-central1-caplight-prod.cloudfunctions.net/api/public
- [Caplight MCP Server](https://www.caplight.com/products/mcp): Hosted remote MCP server at
  https://platform.caplight.com/mcp. 15 documented tools. Added to Claude.ai or Claude Desktop as a
  custom connector; authorized with a Caplight account over OAuth, no API key needed.
- [Embed API](https://www.caplight.com/products/api): One-line embeddable widget rendering live
  MarketPrice quotes, fund marks and order activity inside a customer application.

## Specs

- [OpenAPI 3.1.0 (live)](https://us-central1-caplight-prod.cloudfunctions.net/api/v2/spec)
- [OpenAPI 3.1.0 (harvested copy)](openapi/caplight-rest-api-openapi-original.json)
- [OAuth authorization-server metadata, RFC 8414](https://platform.caplight.com/.well-known/oauth-authorization-server)
- [OAuth protected-resource metadata, RFC 9728](https://platform.caplight.com/.well-known/oauth-protected-resource)

## Docs

- [API reference (Redoc)](https://platform.caplight.com/api/documentation.html)
- [API & MCP product page](https://www.caplight.com/products/api)
- [MCP setup guide](https://www.caplight.com/products/mcp)
- [Changelog](https://www.caplight.com/changelog)
- [Research & blog](https://www.caplight.com/insights)
- [Terms of use](https://www.caplight.com/legal/terms-of-use)
- [Privacy policy](https://www.caplight.com/legal/privacy-policy)

## How to call it

- REST auth: send the header `api_key: <your key>`. Every operation requires it; an anonymous call
  returns 401 `{"message":"Invalid/missing API key. ..."}`. Keys are issued on request to
  contact@caplight.com — API access is a paid add-on to Caplight Data, there is no self-serve signup.
- Pagination: `pageNumber` (1-based) and `pageSize` query params; list responses carry a `pagination`
  object with `pageNumber`, `numPages`, `totalRecords`.
- Company identity: v1 and v2 company IDs are different. Resolve a domain, a PitchBook ID or a v1 ID to
  a v2 ID with `GET /v2/companies` (up to 50 identifiers per request). Both IDs come back in `caplightIds`.
- Entitlements: v2 company-scoped endpoints enforce per-account whitelists and an annual distinct-company
  cap; field-level restrictions omit fields and name them in `restricted.fields`. Always check for a
  `restricted` object.
- Errors: application/json, not RFC 9457. Shapes are `{"status":"error","error":"..."}` and `{"message":"..."}`.
- Sandbox: a staging host is published at
  https://us-central1-caplight-staging.cloudfunctions.net/api/public and requires the same api_key auth.
- Rate limits: none published; no rate-limit headers observed.

## API Evangelist artifacts

- [Authentication profile](authentication/caplight-authentication.yml)
- [Conventions](conventions/caplight-conventions.yml)
- [Error catalog](errors/caplight-problem-types.yml)
- [Data model](data-model/caplight-data-model.yml)
- [Lifecycle](lifecycle/caplight-lifecycle.yml)
- [Changelog](changelog/caplight-changelog.yml)
- [Conformance](conformance/caplight-conformance.yml)
- [Sandbox](sandbox/caplight-sandbox.yml)
- [MCP manifest](mcp/caplight-mcp.yml)
- [MCP tool crosswalk](mcp/caplight-tool-crosswalk.yml)
- [Well-known index](well-known/caplight-well-known.yml)
- [Domain security](security/caplight-domain-security.yml)
- [Embedded components](components/caplight-components.yml)
- [Agent skills](skills/_index.yml)