ExactOnce

The service provides an HTTP API that lets developers create and manage actions that can be executed exactly once. An action is identified by a unique ID, can carry an arbitrary payload, and is bound by optional time windows (active_at and expires_at). When a consumer requests to consume the action, the system atomically resolves concurrent requests so that only a single request succeeds, returning a clear error for any other attempts. Optional PIN protection adds a second factor, and each action records creation and consumption timestamps together with consumer metadata, forming an immutable audit trail.

Typical use cases include invite codes, one‑time passwords, or any workflow where duplicate execution would cause errors. The API supports bulk creation via CSV upload, allowing thousands of actions to be generated in a single request, and it defines explicit failure states such as already_used, expired, not_active, and action_not_found. All endpoints are RESTful, authenticated with client credentials, and return JSON responses with typed error codes.

The platform is positioned as an opinionated, contract‑driven solution that eliminates the need for custom race‑condition handling or cleanup jobs. It targets developers who need reliable, time‑bounded, idempotent execution of single‑use actions and require a built‑in audit log for compliance purposes.