Open-source Calendly. That's it. That's the pitch. Cal.com is a scheduling platform that does everything Calendly does but you can self-host it, customize it, and never pay for the features Calendly locks behind a paywall. The open-source model has attracted a massive developer community. 40,000+ GitHub stars. Thousands of companies use it. In a world where every SaaS tool costs $15/month per user, Cal.com said: what if scheduling was free and open? Turns out, a lot of people wanted that.
Founded
2020
HQ
San Francisco, USA
Total Raised
$32 million
Founder
Peer Richelsen, Bailey Pumfleet
Status
Private
Website
cal.comTHE ORIGIN STORY
Peer Richelsen was frustrated with Calendly. It worked fine, but it was expensive for teams, lacked customization, and locked features behind paywalls.
In 2020, he started building an open-source alternative. Bailey Pumfleet joined as co-founder.
They launched Cal.com (originally Calendso) as a fully open-source scheduling platform. Developers loved it — the project quickly gained tens of thousands of GitHub stars.
Companies started self-hosting it. Cal.com offered a hosted version for those who didn't want to manage infrastructure.
WHAT THEY ACTUALLY DO
Open-core model. The core scheduling product is free and open-source.
Cal.com makes money from: 1) Cal.com Cloud — a hosted version with additional features ($15-$25/user/month). 2) Enterprise plans — advanced features like SSO, compliance, and custom branding.
3) Cal.com Platform — APIs for developers embedding scheduling into their own products.
THE PRODUCTS
Cal.com Scheduling — open-source scheduling links (like Calendly). Round-Robin Routing — distribute meetings across team members.
Workflow Automations — automated reminders, follow-ups, and integrations. Cal.com Platform — APIs for embedding scheduling in any product.
Cal.com Atoms — pre-built UI components for developers.
HOW THEY GREW
Open-source community. The GitHub community drove awareness organically.
Developers who found Cal.com through open-source recommended it within their organizations. The "Calendly but you own it" positioning resonated with privacy-conscious companies and developers who wanted customization.
THE HARD PART
Calendly has massive market share and brand recognition. Most non-technical users have never heard of Cal.com and would just use Calendly.
The open-source model means many users never pay — converting free users to paid is the eternal challenge. SavvyCal and other scheduling tools also compete.
MONEY TRAIL
Seed
2021 · Led by Open Core Ventures
$8M raised
Series A
2022 · Led by Various
$25M raised
WHO BACKED THEM
Backed by Open Core Ventures (the open-source VC firm), Y Combinator, Dick Costolo (former Twitter CEO), and various angel investors.
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