# API Documentation ## Client API This describes the API provided to unleash-clients. * [Feature Toggles API](client/feature-toggles-api.md) * [Register API](client/register-api.md) * [Metrics API](client/metrics-api.md) ## Admin API (internal) The internal API used by the Admin UI (unleash-frontend): * [Feature Toggles API](admin/feature-toggles-api.md) * [Strategies API](admin/strategies-api.md) * [Events API](admin/events-api.md) * [Metrics API](admin/metrics-api.md) ## System API's * [Internal Backstage API](internal-backstage-api.md)