Cal.com
Open scheduling infrastructure company, now closing its source code after 5 years as an open alternative to Calendly.
On the record
Checkpoint: Two-quarter window to show Cal.ai revenue or enterprise retention data after the closed-source pivot
The call
Cal.com gave up the open-source identity that made it different from Calendly right as AI agents start booking meetings without any scheduling link at all.
Cal.com helps people and businesses schedule meetings online, similar to Calendly but smaller and cheaper. The company used to let customers run it on their own servers and shared all its code with the public, which made it trustworthy and hard to replace. But in April 2026, the company locked down its code for security reasons, erasing what made it different. Now Calendly is four times bigger and better funded, and Google and Microsoft are building scheduling straight into their apps with AI that may do the job without needing a separate tool. The one thing that could save Cal.com is if its embedded API for developers becomes truly sticky and keeps customers locked in, but there is little public evidence this is actually happening.
Why
01
AI pressure: Native AI scheduling agents in Google Calendar, Outlook, and ChatGPT. If Gmail or Outlook books meetings by itself, a separate scheduling link app has less reason to exist for most users. Could AI do the core job? Yes, likely.
02
Bigger players: Calendly. Calendly has 4x the traffic, $350M raised, and a $3B valuation while Cal.com sits near $5M ARR and 44 people. Could a giant copy it? Yes, easily.
03
What protects it. Embedded Atoms API components already wired into other companies' products create real, if modest, switching costs.
What would change this call
Cal.com discloses enterprise or community churn numbers after its April 2026 closed-source pivot. Would show whether abandoning open-source cost it the trust-based customer base.
Calendly launches its own embeddable API or developer-first scheduling tier. Would show the incumbent closing Cal.com's remaining structural gap.
Google or Microsoft ships a native AI scheduling agent inside Calendar or Outlook with visible adoption. Would confirm the category is being absorbed by platform AI rather than dedicated scheduling tools.
Calendly launches its own embeddable API or developer-first scheduling tier. Would show the incumbent closing Cal.com's remaining structural gap.
Google or Microsoft ships a native AI scheduling agent inside Calendar or Outlook with visible adoption. Would confirm the category is being absorbed by platform AI rather than dedicated scheduling tools.
Key numbers
- ~$5.1M ARR as of Oct 2024
- 825 companies actively running its widget
- ~44 employees as of mid-2026
Named risks
- April 2026 closed-source pivot triggers developer community and enterprise churn.
- Native AI calendar agents from Google, Microsoft, or Anthropic could subsume core scheduling workflow.
- Revenue and headcount figures beyond Nov 2023 self-report remain unverified across conflicting third-party estimates.
- Calendly, a 4x larger incumbent, could add competing AI scheduling features and close Cal.com's differentiation window.
Rivals, as read in July 2026
| Rival | Direction | Evidence |
|---|---|---|
| Calendly | losing to | Calendly raised $350M at ~$3B valuation Jan 2021 versus Cal.com's ~$32.4M total disclosed funding |
| Calendly | contesting | Cal.com competes on open API/Atoms embeddable components while Calendly is the slower-moving incumbent |
| Google/Microsoft native AI calendar agents | losing to | Native AI scheduling agents in Google Calendar and Outlook threaten to subsume booking-link workflows by 2026 |
Questions people ask
- Is Cal.com profitable in 2026?
- No public profitability figures exist. Cal.com self-reported $1M ARR with 13,667 monthly active users as of November 14, 2023, its last disclosed open-metrics update; no profit or later self-reported revenue figures have been published since.
- Did Cal.com abandon open source?
- Yes. On April 28, 2026, CEO Bailey Pumfleet announced Cal.com is moving its core codebase from open-source (AGPLv3) to a closed, proprietary license, citing AI models like Anthropic's Mythos scanning open code for vulnerabilities.
- Who founded Cal.com and who runs it?
- Cal.com was founded in 2021, originally launched as Calendso before rebranding. Co-founders are CEO Bailey Pumfleet and Peer Richelsen, confirmed in reporting on the company's April 28, 2026 closed-source pivot announcement.
- Who is Cal.com's biggest competitor?
- Calendly is Cal.com's primary competitor and the category incumbent, having raised $350M at a reported $3B valuation in January 2021, versus Cal.com's disclosed total of about $32.4M raised through 2022.
- Could AI replace Cal.com's product?
- The core scheduling-link workflow is exposed to AI calendar agents from Google, Microsoft, or Anthropic that could negotiate meetings directly. Cal.com launched its own Cal.ai phone-booking agent on September 14, 2025, priced at $0.29 per minute, to pre-empt this.
- How much funding has Cal.com raised?
- Cal.com raised a $7.35M to $7.4M seed round in December 2021 led by OSS Capital, followed by a $25M Series A in April 2022 led by Seven Seven Six, for roughly $32.4M in disclosed funding as of 2022.
Timeline
- 2026-04-28Cal.com announces core codebase moves from open-source AGPLv3 to closed, proprietary license
- 2026-04-15Cal.com launches Cal.diy, an MIT-licensed community fork, alongside closed-source pivot
- 2025-09-14Cal.com launches Cal.ai phone-agent scheduling assistant at $0.29 per minute
- 2023-11-14Cal.com self-reports $1M ARR, 13,667 MAU, 25,500 GitHub stars in v3.6 update
- 2023-10-16Cal.com launches original Cal.ai email/chat scheduling assistant
- 2022-04-28Cal.com raises $25M Series A led by Seven Seven Six
- 2021-12Cal.com raises $7.4M seed round led by OSS Capital
- 2021Company founded as Calendso, later rebranded to Cal.com
Revision history
23 July 2026
First assessed. Losing its protection. The text above is fixed as of this date and is not edited afterwards.
In the same band
Sources
- Cal.com, Inc. raises $7.4m Seed (2022-09-08)
- Open source Calendly rival Cal.com raises $25M (2022-04-28)
- Cal.com Stock Price, Funding, Valuation
- $5.1M ARR, $150M Valuation (2026-07-02)
- Cal.com 2026 Company Profile
- Revenue, Competitors, Alternatives
- Cal.com v3.6 (2023-11-14)
- Companies that use Cal.com (2026-07-15)
- What is Customer Demographics of Cal.com (2026-03-18)
- Cal.com v5.7 - Cal.ai phone agent (2025-09-14)
- Cal.com Launches Cal.ai (2023-10-16)
- 'Like handing out the blueprint to a bank vault' (2026-04-28)