Best open-source alternatives to Calendly

Cal.diy is a community-driven scheduling platform intended for people who want to self-host their own appointment booking infrastructure. It is presented as the open-source community edition of Cal.com, with enterprise and commercial code removed, and the README emphasizes that it is best suited for personal, non-production use. The project targets self-hosters and developers who want full control over their scheduling stack. It uses a modern web stack centered on Next.js, tRPC, React, Tailwind CSS, Prisma, and Daily.co. The README describes both local development setup and a quick-start path using Docker and Docker Compose, along with manual database configuration, migrations, and tools for inspecting seeded users and development emails.

Cal.diy is a community-driven, MIT-licensed scheduling platform forked from Cal.com and intended for self-hosters who want to run their own booking infrastructure. The project positions itself as a fully open-source alternative with all enterprise and commercial code removed, and it explicitly warns that it is best suited for personal, non-production use. It is aimed at developers and administrators comfortable managing servers, databases, and application secrets. The README describes a local development workflow using Node.js, PostgreSQL, Yarn, and optional Docker-based quick start tooling, along with manual database setup and Prisma migrations. It also notes seeded test users, browser access on localhost, and development tools such as Mailhog for inspecting email.

Rallly is a self-hostable scheduling tool designed to help people organize group meetings without long email threads. It lets users create meeting polls so participants can indicate when they are available, making it easier to choose a date and time that works for everyone. The project is positioned for friends, colleagues, and teams that need a simple way to coordinate events. The application is built with Next.js, Prisma, tRPC, and TailwindCSS, and the README includes instructions for running a local development environment. It relies on a Docker-based database setup for local installation, and the project points users to separate self-hosting documentation and configuration options for running their own instance. The code is released under the GNU AGPLv3 or later, indicating an open-source, self-hosted deployment model.

Easy!Appointments is a self-hosted appointment scheduling web application aimed at businesses and service providers that need to let customers book appointments online. The project emphasizes customization, making it suitable for different workflows and commercial use while remaining deployable on a server alongside an existing website and database. It includes core scheduling tools for managing customers, appointments, services, providers, working plans, and booking rules. The README also highlights Google Calendar synchronization, email notifications, and a translated interface. Installation is done by copying the source to a server and configuring it for a PHP/MySQL stack, with local development supported via Node.js, npm, and Composer.