Rallly vs Cal.com: Open Source Scheduling Tools in 2026

The Scheduling Tool Problem

Calendly charges $10-20/user/month. Doodle charges for features that should be free. Both send your meeting data through their servers.

The open source scheduling landscape has split into two clear use cases:

1. Group availability polling (like Doodle): "When can everyone meet?" — This is Rallly
2. Individual booking pages (like Calendly): "Book time on my calendar" — This is Cal.com

Understanding which use case you need makes the choice straightforward.

TL;DR

• Rallly (5K+ stars): Best for group scheduling polls. Share a link, everyone marks availability, find the best time. Open source Doodle alternative. No accounts required for participants.
• Cal.com (35K+ stars): Best for individual booking pages. Share your booking link, others book time based on your calendar availability. Complete open source Calendly alternative.

Quick Comparison

Feature	Rallly	Cal.com
GitHub Stars	5K+	35K+
Primary use case	Group availability polls	Individual booking links
Calendar sync	Limited	Full (Google, Outlook, iCal)
No account needed for guests	Yes	Yes
Team scheduling	Yes (via polls)	Yes (round-robin, etc.)
Payments	No	Yes
Video conferencing	No	Yes (Zoom, Meet, etc.)
Workflows/automations	No	Yes
Self-hosting	Easy	Medium
License	AGPL-3.0	AGPL-3.0

Rallly — Best Group Availability Polling

Rallly is a focused tool for one thing: figuring out when a group of people can meet. Create a poll with time options, share a link, participants mark their availability — no accounts required.

What Makes It Stand Out

Zero friction for participants: Share a poll link, others click their available times. No Rallly account needed for responders. This is the single biggest advantage over many alternatives.

Clean interface: The scheduling grid is intuitive — rows for people, columns for time slots, marks for availability. At a glance, you see when everyone is free.

Comments: Add discussion to the poll — context, notes, or final confirmation of the chosen time.

Email notifications: Notify all participants when you finalize a time.

Final date: Mark the selected time as final, automatically notify all participants.

Use Cases

• Team meeting scheduling across multiple people
• Recurring meeting time selection ("When should we schedule our weekly standup?")
• Event planning with external participants who don't have accounts
• Conference scheduling, workshop slots

Self-Hosting

git clone https://github.com/lukevella/rallly-selfhosted
cd rallly-selfhosted
cp .env.example .env
# Configure email settings
docker compose up -d

Rallly runs as a single Docker container with PostgreSQL. Very simple deployment — one of the easiest self-hosting setups in this article series.

Email configuration: Rallly needs an SMTP provider to send invitation and notification emails. Configure with any SMTP service (Gmail, Resend, AWS SES).

Limitations

• Not a Calendly replacement: Rallly doesn't sync with your calendar or provide a "book a time on my calendar" link. It's group polling, not booking.
• No individual scheduling pages
• No calendar integrations
• No payment processing

Best for: Teams scheduling internal meetings, event organizers coordinating group availability, anyone who needs a free Doodle alternative.

Cal.com — Complete Calendly Replacement

Cal.com (35K+ stars) is the most comprehensive open source scheduling platform. It provides everything Calendly offers — booking pages, calendar sync, team scheduling, workflows, and payments — in a self-hostable package.

What Makes It Stand Out

Calendar sync: Two-way sync with Google Calendar, Outlook, iCloud, and CalDAV. Blocks time when you're busy based on your actual calendar.

Event types: Create different booking types:

• 15-min consultation
• 60-min project kickoff
• Recurring office hours
• Custom durations

Team scheduling:

• Round-robin: Distribute bookings among team members based on availability
• Collective: Require all team members to be available
• Individual: Book with a specific person

Availability settings: Set working hours, date ranges, buffer time between meetings, minimum notice period.

Integrations: Zoom, Google Meet, Microsoft Teams, Webex — auto-generate video conference links for bookings.

Payments: Integrate with Stripe to charge for consultations or sessions.

Workflows: Automated emails before/after meetings, SMS reminders, webhook triggers.

Embed: Embed your booking widget on any website.

Self-Hosting

Cal.com has a more complex self-hosting setup than Rallly:

git clone https://github.com/calcom/cal.com
cd cal.com
cp .env.example .env
# Configure:
# - DATABASE_URL (PostgreSQL)
# - NEXTAUTH_SECRET
# - CALENDSO_ENCRYPTION_KEY
# - Email SMTP
# - Calendar OAuth credentials (optional)
yarn install
yarn db:deploy
yarn build
yarn start

Or using Docker:

docker compose -f docker-compose.yml up -d

Cal.com requires PostgreSQL, Redis, and the main application. More setup than Rallly but well-documented.

Cal.com Cloud: The managed cloud service (cal.com) has a free tier for individuals and paid plans for teams ($12/user/month). Self-host if you need unlimited users or data residency.

Limitations

• More complex to self-host than Rallly
• Requires OAuth setup for calendar integrations (Google OAuth app configuration)
• No group availability polling like Rallly

Best for: Freelancers, consultants, sales teams, and any individual or organization that needs an appointment booking system.

Using Both Together

Many teams use both tools for different scenarios:

Use Rallly for: Initial team meeting time selection, conference scheduling, group coordination

Use Cal.com for: Client booking links, intake consultations, recurring office hours, any "book with me" use case

Cost Comparison

Commercial Tools Annual Costs

Tool	Plan	Per User/Month	Annual (5 users)
Calendly	Essentials	$8	$480
Calendly	Professional	$12	$720
Doodle	Business	$14.95	$897

Self-Hosted

Tool	Server	Annual
Rallly (Hetzner CAX11)	$4/mo	$48
Cal.com (Hetzner CPX21)	$6.50/mo	$78
Both on same server	$10/mo	$120

You can run both Rallly and Cal.com on a single $10/month VPS, replacing $480-897/year in commercial tool subscriptions.

Migration from Doodle to Rallly

Rallly's core use case (time polls) maps directly to Doodle:

1. Create a new poll in Rallly
2. Add the same time options you'd add in Doodle
3. Copy and share the poll link
4. Participants interact the same way — no accounts needed

The migration is behavioral (team members learn to use a new link), not technical.

Migration from Calendly to Cal.com

Calendly and Cal.com have similar workflows:

1. Set up Cal.com (self-hosted or cloud)
2. Connect your calendar (Google/Outlook)
3. Configure your availability
4. Create event types matching your Calendly types
5. Update your booking link on your website and email signature
6. Cancel Calendly subscription

Historical booking data doesn't transfer, but since scheduling is forward-looking (you care about future bookings, not past ones), this is rarely a concern.

Why Open Source Scheduling Matters in 2026

The commercial scheduling market has consolidated around a handful of vendors who charge per-seat monthly fees for functionality that, in most cases, doesn't justify those recurring costs. Calendly's pricing — $8-12/user/month — adds up to $480-1440/year for a five-person team. Doodle's business plan charges $14.95/user/month. Both tools handle data about your meeting availability, participants, and calendar entries on their own servers.

Open source scheduling tools flip this model. Self-hosting Rallly and Cal.com on a single VPS costs $10-15/month regardless of team size. Your scheduling data — who you meet with, how often, what times you prefer — stays on your server. And you're not dependent on a vendor deciding to change pricing, deprecate features, or shut down.

The market signal for open source scheduling is strong. Cal.com's 35K+ GitHub stars reflect genuine adoption, not just curiosity. Companies including Y Combinator startups, enterprise teams, and independent consultants use Cal.com in production. Rallly's growing community has validated the group polling use case as a standalone product rather than a feature bundled into a larger platform.

Understanding the total cost picture — including the hidden costs of lock-in to commercial scheduling tools — is worthwhile before committing to any platform. The hidden costs of SaaS vendor lock-in analysis applies directly here: migrating away from Calendly later requires updating every booking link on your website, in your email signatures, and in any automation that references your Calendly URL.

How to Choose the Right Scheduling Tool for Your Team

The Rallly vs Cal.com decision is essentially a use-case decision, not a quality decision. Both tools are production-ready and actively maintained. The question is what problem you're primarily trying to solve.

If your primary need is coordinating group availability — figuring out when three to twenty people can meet — Rallly solves this with less setup friction than Cal.com. The no-account requirement for poll participants is a significant practical advantage. When you're scheduling with external participants (clients, partners, candidates), removing the sign-up barrier improves response rates meaningfully. Rallly is also simpler to deploy and maintain.

If your primary need is individual booking pages — letting others schedule time with you based on your calendar availability — Cal.com is the answer. The feature set directly mirrors Calendly: event types, calendar sync, video conferencing integration, team routing, and workflows. Self-hosted Cal.com provides these features at infrastructure cost only.

Teams with both use cases should consider running both tools. The infrastructure overhead is minimal — both can share a single VPS with enough resources for typical team usage.

For broader context on open source scheduling tools beyond Rallly and Cal.com, see Best Open Source Scheduling Tools 2026, which covers additional options for teams with more specific requirements. Teams replacing Calendly specifically will find Best Open Source Alternatives to Calendly 2026 useful for a direct feature comparison and migration guide.

Real-World Deployment Considerations

Both tools have specific operational requirements worth understanding before deploying to production.

Rallly's most critical operational dependency is email. Every core workflow — sending poll invitations, notifying participants of updates, confirming the final meeting time — requires working SMTP configuration. A broken email configuration silently breaks Rallly's core functionality. Before going live, test the full email flow: create a poll, invite participants, finalize a time, and verify that all notifications arrive correctly. Configure an SMTP provider (AWS SES, Resend, Postmark) rather than relying on Gmail's SMTP, which has rate limits that can interrupt notifications on busy instances.

Cal.com's calendar sync is what makes the booking experience valuable, but it requires OAuth application configuration that adds setup complexity. Connecting Google Calendar requires creating a Google Cloud project, enabling the Calendar API, and configuring an OAuth client with the correct redirect URIs. This is well-documented in Cal.com's deployment guide but is a multi-step process that can take 30-60 minutes for developers unfamiliar with Google Cloud Console. If calendar sync is critical, plan for this setup time and test OAuth flows in staging before production deployment.

Both tools benefit from being deployed behind a reverse proxy (Caddy or Nginx) that handles HTTPS termination. Scheduling tools collect calendar availability data and potentially payment information — HTTPS is not optional. Caddy's automatic TLS via Let's Encrypt makes this straightforward for most deployments.

Database backups deserve attention from day one. Cal.com stores your event types, bookings, and availability rules in PostgreSQL. A backup failure discovered after a database corruption event means losing all historical booking data and having to reconfigure every event type from scratch. Automate daily PostgreSQL dumps to an external location and test restoration quarterly.

Find Your Scheduling Tool

Browse all scheduling tools on OSSAlt — compare Rallly, Cal.com, and every other open source scheduling and calendar tool with deployment guides and feature comparisons.

See open source alternatives to Rallly on OSSAlt.