Build on the system of record founders actually use
Register an OAuth app, request the scopes you need, and read a company’s cap table, investors, data room, and forecast with the founder’s consent. First-class API keys, webhooks, and a signed OpenAPI contract.
OAuth 2.0 + PKCE
Standards-based authorization. Redirect a founder to Arx, request fine-grained scopes, and exchange a code for tokens.
API keys
For server-to-server automations, mint scoped API keys per app and environment. Secrets are shown once and hashed at rest.
Webhooks
Subscribe to cap table, investor, and data room events. Inspect every delivery attempt and redeliver failures.
Quickstart
Register an app, run the authorize + PKCE flow, exchange your code, and call your first endpoint in minutes.
API reference
The full, live OpenAPI 3.1 contract — every endpoint, method, and scope, generated straight from the API.
Manage apps
Credentials, installs, keys, webhooks, and usage — everything about your integrations in one place.