Timekit

Timekit is scheduling infrastructure for developers and platforms that want to build booking directly into their own product rather than send users to a third-party link. It exposes a REST API and web app for creating resources, defining availability and booking rules, matching availability across participants, and managing users and permissions — the plumbing behind a custom booking experience.

Because it is API-first, teams can invite staff, create inventory, or connect their platform's own users via the API, then either embed Timekit's widget or build a fully custom booking form. Integration can be driven from the admin dashboard or entirely through the API, including building a custom mini-admin. It handles calendar synchronization with Google Calendar and Outlook, automated reminders, and room or resource booking for shared spaces.

Pricing reflects its developer focus: plans start around $49 per month, and there is no fully free plan — signing up puts you in a test mode with a 14-day API trial and free-forever access to the admin interface, limited to receiving bookings at your own email. Timekit is web- and API-based. It fits SaaS products and marketplaces that need scheduling as an embedded, brandable feature rather than a standalone app.