Cal.diy vs Rallly
Both are alternatives to Calendly. Here's how they stack up — verified facts, no spin.
Also searched as Rallly vs Cal.diy — same comparison, one verdict.
Cal.diy and Rallly are closely matched on ownership (85 vs 84) — this one comes down to pricing and to which trade-offs below you can live with.
Cal.diy
MIT-licensed community edition of the Cal.com scheduling codebase.
Cal.diy is the free, permissively-licensed fork Cal.com released in April 2026 after taking its commercial product closed-source. It carries over Cal.com's core booking engine — event types, buffer/booking-limit rules, Stripe/PayPal payments, and calendar/video integrations — under the MIT license, but the maintainers themselves describe it as community-maintained and recommend it for personal, non-production use rather than as a supported business tool.
Rallly
Open-source group scheduling and meeting-time polling.
Rallly solves a different but related problem: instead of one person publishing a booking link, it lets a group vote on the best time for a meeting across several proposed slots — the open-source answer to Doodle that also covers a chunk of Calendly's group-scheduling use case. It's actively developed and offers a hosted version (rallly.co) alongside a documented self-hosted Docker deployment.
Side by side
10 points of comparison, every one read from a verified field. Green marks the side that wins a row outright. A dash means we do not hold that fact — never that it is zero.
| Cal.diy | Rallly | |
|---|---|---|
| Sovereignty ScoreOur transparent 0–100 composite for data ownership and exit cost. | 85 | 84 |
| Open source | Yes | Yes |
| Self-hostable | Yes | Yes |
| Local-first data | Yes | Yes |
| License | MIT | AGPL-3.0 |
| Pricing | Free, self-hosted. No official managed hosting or support channel; Cal.com's paid hosted product is a separate, now closed-source, offering. | Free, self-hosted via Docker. A hosted version exists at rallly.co with an optional paid Pro tier for extra features. |
| RAM to run it wellThe figure that actually matters, not the vendor's minimum. | 2 GB to run the built image with PostgreSQL and Redis; 8 GB on whichever machine does the build | 2 GB covers the bundled stack (Traefik, PostgreSQL, Garage object storage and the app) for a team's polls |
| Realistic running costWhat the box costs each month if you run it yourself. | $6–12/mo on a 2 GB VPS, as long as you build the image on an 8 GB machine you already own and push it to a registry | $6–12/mo on a 2 GB VPS plus a transactional email provider. Free for one registered account; a one-off $49 licence covers up to 5 (guest voters don't count) |
| Setup timeHonest first-install estimate, not the marketing quickstart. | Half a day for the first build and deploy, and every upgrade or domain change means another rebuild | 30 minutes with the installer script, if DNS and SMTP are ready first |
| Ongoing maintenanceThe part nobody budgets for. | There are no tagged cal.diy releases since the April 2026 fork, so upgrading means pulling main, rebuilding and running database migrations. Some features need cron jobs you set up yourself, and each integration (Google, Microsoft, Zoom) needs developer credentials you create. | ./rallly.sh update pulls new 4.x images. ./rallly.sh backup dumps PostgreSQL only, so copy backups off the server and back up the garage-data volume separately if people upload files. Edit only .env, because updates overwrite the other stack files. |
Cal.diy edges it on the Sovereignty Score, but the right pick depends on the trade-offs below.
Weighing both against staying on Calendly? Is Calendly free? What it actually costs →
Cal.diy
Strengths
- +Fully MIT-licensed — no open-core split, no feature paywall, free to modify or redistribute
- +Inherits a feature-rich booking engine: recurring events, seated events, payments, wide calendar/video integration list
- +REST API and embeddable booking widgets for building your own booking flow
- +Active repo (46k+ stars, commits within days) even post-fork
Trade-offs
- −Its own docs recommend it for personal use only and disclaim production readiness — 'use at your own risk'
- −No official support; the parent company no longer backs this codebase
- −Missing team/organization features, SSO/SAML, workflows, and routing forms that stayed in Cal.com's closed-source enterprise edition
- −Requires running Postgres + Redis + a Node.js host yourself — more moving parts than a single-binary app
- −Young as an independent project (forked April 2026); long-term maintenance commitment is unproven
Rallly
Strengths
- +Simple, focused tool that's genuinely good at the group-availability-poll problem
- +Active project (5,100+ stars, commits within the last day) with a documented Docker Compose deployment
- +AGPL-3.0 keeps improvements to a hosted fork open
Trade-offs
- −Not a 1:1 booking-page replacement — no per-provider service catalog, payments, or staff management like Calendly/Easy!Appointments
- −Primary distribution is the hosted rallly.co app; self-hosting is supported but secondary in the project's own messaging
- −AGPL-3.0 requires you to publish modifications if you offer a modified version as a network service
Which one fits you
The trade-offs above, turned into a decision. Find the line that describes your team.
Choose Cal.diy
if a lower exit cost matters more to you than any single feature, and fully MIT-licensed — no open-core split, no feature paywall, free to modify or redistribute.
Choose Rallly
if simple, focused tool that's genuinely good at the group-availability-poll problem.
Neither, yet
if both carry a real cost you should weigh first — its own docs recommend it for personal use only and disclaim production readiness — 'use at your own risk', and not a 1:1 booking-page replacement — no per-provider service catalog, payments, or staff management like Calendly/Easy!Appointments. If either of those is a dealbreaker for your team, the shortlist is wrong rather than the choice.
What it takes to run these yourself
Real requirements and honest running costs, not the vendor quickstart.
Self-hosting Cal.diy
2 GB to run the built image with PostgreSQL and Redis; 8 GB on whichever machine does the build RAM · Half a day for the first build and deploy, and every upgrade or domain change means another rebuild
$6–12/mo on a 2 GB VPS, as long as you build the image on an 8 GB machine you already own and push it to a registry
Self-hosting Rallly
2 GB covers the bundled stack (Traefik, PostgreSQL, Garage object storage and the app) for a team's polls RAM · 30 minutes with the installer script, if DNS and SMTP are ready first
$6–12/mo on a 2 GB VPS plus a transactional email provider. Free for one registered account; a one-off $49 licence covers up to 5 (guest voters don't count)
Cal.diy vs Rallly — common questions
Is Cal.diy a better fit than Rallly for scheduling & booking?
It depends on what you are optimising for, and the honest split is this: Cal.diy scores 85 to Rallly's 84 on data ownership and exit cost, so it is the safer choice if you care about being able to leave. Rallly earns its place on a different axis — simple, focused tool that's genuinely good at the group-availability-poll problem. Neither is a wrong answer for every team; the table above is the actual comparison.
What happens if we want to switch later?
Cal.diy keeps its data local or in open formats, so leaving is an export rather than a negotiation. Rallly is still self-hostable, so the files stay on your server either way — but it is not local-first by design, so check what its export produces before you rely on it.
Can I self-host Cal.diy or Rallly?
Both can be self-hosted. The difference is what it costs you in time rather than whether it is possible — see the setup and maintenance rows above.
Are Cal.diy and Rallly both alternatives to Calendly?
Yes — both appear in our Calendly comparison, which is why they are worth putting side by side. People usually arrive here already having decided to move off Calendly and now choosing between the two replacements, which is a narrower and much easier question.
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Facts verified 2026-07-09. Licenses and pricing change — spotted something out of date? That's a correction we want.