Open source Calendly alternatives in 2026: read the license before you self-host

Most open source Calendly alternatives lists still point you at Cal.com's public repository. That repository is now Cal.diy: MIT-licensed, free to run, and shipped without Teams, Organizations, Workflows, Insights and SSO/SAML, which were removed when Cal.com moved its production code private in April 2026. If you are one person who wants a booking page on your own server, that is still a good deal. If you need round-robin routing across a sales team, no free self-hosted option covers it today.

This is a comparison of the four projects we think are worth running in October 2026, judged on the license you get, what each one leaves out, and what self-hosting actually costs next to Calendly's paid seats.

Is Cal.com still open source? The code you would run moved in April 2026

Cal.com is still open core, but the code in the public repository is no longer the code that runs the hosted product. In an engineering post dated April 15, 2026, Cal.com described moving its production codebase into a private repository and renaming and relicensing the public one as Cal.diy, from AGPL-3.0 to MIT.

The post lists what came out of the open edition: Organizations and Teams, Routing Forms, Workflows, Instant Booking, AI Phone, attributes and segments, the SAML/SSO signup flow, Insights, API v1, enterprise UI such as the license wizard and billing screens, booking audit logging and admin impersonation. Cal.diy keeps the core scheduling engine, the app store, booking flows and API v2.

That matters for anyone comparing options from a 2024 listicle, because two things people assume about "self-hosted Cal.com" are no longer true. You are not running the same build as the cloud product, and you are not getting the team features the Cal.com marketing site shows. Cal.com is listed on Upfynd in Calendar & Scheduling, and we would now read its listing as two products: a hosted service, and a community fork.

The license swap is the one piece of good news for integrators. AGPL-3.0 obliges you to publish your changes if you serve the software over a network; MIT does not. If you intended to fork a booking flow into your own product, Cal.diy is the first version of this codebase you can do that with quietly.

Open source Calendly alternatives compared: four you can actually run

Each of these is a project whose license and docs we read on October 23, 2026. Features and prices change, so check the same pages before you commit a weekend to a deployment.

Cal.diy: the MIT fork, best for one person with a server

Cal.diy's README states the project is 100% MIT-licensed with no proprietary enterprise edition, needs no license key and no Cal.com account, and requires Node.js 18 or later and PostgreSQL 13 or later. There is a published Docker image and a Docker Compose path, so you are not building from source unless you want to.

Read the warning at the top of that README before you plan anything around it: it says use is at your own risk, that Cal.diy is "strictly recommended for personal, non-production use", and that self-hosting requires advanced server administration and database knowledge. The README also repeats the removals - Teams, Organizations, Insights, Workflows and SSO/SAML are gone.

In our view that warning is a licensing and support statement as much as a technical one, and we would still run it for a single person's booking page. We would not put a client-facing booking flow for a 20-person company on it without someone on staff who is comfortable owning a Next.js app and a Postgres database.

Rallly: group polls, free for one user, paid above that

Rallly solves the other half of the scheduling problem. You post several date and time options, share a link, and people mark availability without creating an account, per its repository, which is AGPL-3.0 and ships as a Docker image.

The part most lists omit is licensing for self-hosted instances. Rallly's own self-hosting licensing page says single-user setups are free, and multi-user setups need a paid license key: Plus at $49 for up to 5 users, Organization at $499 for up to 50, and Enterprise from $999. The page says the license is perpetual for v4.x, that limits run on an honor system, and that unregistered guest voters do not count toward your user limit.

That makes Rallly open source and not free in the way people mean it, above one named user. We think $49 once for a five-person team is the least annoying line item in this whole comparison, but it belongs in your spreadsheet, not in a surprise.

Easy!Appointments: the PHP booking app for service businesses

Easy!Appointments is the pick when the job is appointments rather than meetings - a clinic, a workshop, a studio with several staff and a service menu. Its repository lists GPL-3.0 code, Apache or Nginx with PHP 8.2 or later and MySQL, Google Calendar synchronization, service and provider organization, working plans and booking rules, email notifications and a multi-language interface.

It is also, in our reading, the most conventionally maintained project here: the project site shows v1.6.1 as the current stable release, posted on October 19, 2026. The site's FAQ describes the software as free and open source with no monthly fees or appointment commissions, and sells optional paid services - installation, upgrades, migration, support contracts, customization and white labeling - without listing prices.

Skip it if your stack is Node and Postgres and nobody wants to own a PHP deployment, or if your team lives in Microsoft 365, since the project advertises Google Calendar sync and does not advertise Outlook sync.

Nextcloud Calendar appointments: free if you already run Nextcloud

If you already self-host Nextcloud, you may not need a fourth service at all. The Nextcloud Calendar manual documents appointment slots that people without an account on your instance can book, with public slots discoverable from a user's profile page and private ones reachable only through a secret URL.

The booking page shows title, location, description and length with the available slots for a chosen day, and the attendee supplies a name and email. Nextcloud then emails a confirmation link, and the booking is only accepted and sent to the organizer once the attendee clicks it. The manual also notes the trade-off: an unconfirmed slot still shows as bookable, and if someone else confirms it first, the conflict is detected and a new time offered.

For a team that already pays for Nextcloud hosting, we think this is the cheapest honest answer on the page. Upfynd lists 211 products in Open Source as of October 2026, and a suite you already run is worth checking for a booking feature before you add a fourth service.

Which open source scheduling tool supports teams? None of these, for free

There is no free self-hosted option in this comparison that routes a booking round-robin across several people with shared availability. Cal.com removed Teams and Organizations from Cal.diy. Rallly's polls are not a booking page. Easy!Appointments organizes providers and services but is built around a business's own staff calendar rather than sales-style routing. Nextcloud's appointments are per user.

So if team routing is the requirement, the honest shortlist is paid: Cal.com's hosted or enterprise plans, Calendly, or one of the hosted booking tools. That is a conclusion we reach from the vendors' own documentation, not a knock on the projects - each of them is clear in writing about what it does not do.

What self-hosting really costs next to Calendly's $10 and $16 seats

Calendly's pricing page, checked on October 23, 2026, lists a free plan with one event type and one calendar connection, Standard at $10 per seat per month, Teams at $16 per seat per month, and Enterprise starting at $15,000 a year with a 50-seat minimum.

Run those numbers against a server. Five people on Calendly Teams is $80 a month, or $960 a year at list price. Five people on a self-hosted stack is a $49 Rallly license once, or nothing at all for Cal.diy, plus a small VPS and the hours someone spends on upgrades, backups, SMTP deliverability and TLS. The arithmetic is ours and the server bill is yours, but the shape of it is consistent: self-hosting wins on cash and loses on attention.

The free Calendly plan is the comparison most people should actually make. One event type and one calendar is enough for a single consultant, and it costs no maintenance at all. We would only self-host over that if you want your booking data on your own infrastructure, need to remove vendor branding without paying, or plan to fork the code.

Skip self-hosting if any of these is true

• Nobody on the team will own patching. A public booking page is an internet-facing app with your calendar behind it.
• You need SSO, audit logs or round-robin now. All three sit on the commercial side of the line in 2026.
• Your calendar is Microsoft 365 and the project you picked documents Google sync only.

If none of those apply, start with Cal.diy's Docker Compose setup for a personal page, or with Nextcloud's appointments if you already run Nextcloud, and treat Rallly as the separate tool it is for finding a time with a group.

If you would rather compare hosted options first, Upfynd lists 156 products in Calendar & Scheduling as of October 2026, including TidyCal, SetMore and YouCanBookMe - check each one's own pricing page, then submit a listing if you maintain a scheduling tool we are missing.