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Capable REST API

Read and write your company's cap table from your own systems: add new hires from your HRIS, feed your finance model, or build an internal equity portal.
The API is included on the Startup and Growth plans, and works in full during the 14-day free trial. There are no per-call fees.

Base URL

Every request goes to this address over HTTPS, and every response is JSON.

https://capable.so/api/v1

Quickstart

  1. 1

    Create an API key

    In Capable, open Settings → Integrations and choose New key. Pick the scopes the integration needs; read scopes are ticked by default. The key starts with cap_ and is shown once, so copy it into your secret store. Open Integrations

  2. 2

    Make your first request

    Ask for the company’s totals. The key decides which company you read, so there is no company id in the URL.

    curl https://capable.so/api/v1/company \
  -H "Authorization: Bearer $CAPABLE_API_KEY"
  3. 3

    Read the response

    200 OK
    {
  "companyId": "org_northwind8k2",
  "asOf": "2026-11-05",
  "totals": {
    "outstandingShares": 9500000,
    "options": 1015000,
    "availablePool": 985000,
    "fullyDiluted": 11500000,
    "safePrincipal": 1250000
  }
}

    The full response has ten totals. See Get company totals.

Where to go next

Authentication

Create a key, choose its scopes, and keep it secret.

Webhooks

Get a signed POST when a grant, exercise or import happens.

Get the cap table

Fully diluted ownership on any date, in one call.

AI connector

Let Claude and ChatGPT read the cap table and propose changes.

Endpoints

11 endpoints cover the cap table, the people on it, every security, the ledger, the data room index and a full OCF export.

Company

Stakeholders

Securities

Records

API or AI connector

Use the API for systems: an HRIS sync, a finance model, an internal portal. Its writes take effect without a second approval, because an admin chose the key’s scopes. Use the AI connector for people working in Claude or ChatGPT: it reads the cap table as the signed-in person, and every change it proposes waits for an admin to approve it.

OpenAPI

The whole API is described in an OpenAPI 3.1 file you can import into Postman, Insomnia or a code generator.

openapi.json