Calendso

Calendso is a free and open source self-hosted Calendly alternative. Calendso is white-label by design and can be hosted on-premise or can be hosted and managed by Calendso for a monthly charge. The calendar software is built to be API-driven and ready to be deployed on your own domain and does not add hurdles to the self-hosting process to favor the managed solution. Calendso provides modern features and comes with integrations for popular third-party services like Salesforce, Zapier, HubSpot and many more. While also allow you and your company to build custom integrations for any platform out there, and integrate seamlessly with your existing workflow.