# Cal.com

> **TL;DR.** Cal.

- **Category:** SaaS / Developer Tools / Open Source
- **Stage:** validating
- **Age:** 49 days
- **Origin date:** 2026-04-15
- **First detected:** 2026-04-16
- **Canonical URL:** https://earlyterms.com/term/cal-com
- **Sources:** 8 primary URLs

## Definition

Cal.com is a scheduling and booking platform — for years the leading open-source alternative to Calendly — that on April 15, 2026 announced it is closing its core codebase. The production app now lives in a private repo; the previously-public AGPL repo has been rebranded [Cal.diy](https://cal.com/blog/cal-diy-open-source-to-closed-source), relicensed MIT, and slimmed to a community edition.

The term is emerging this week as a news event, not a new product: Cal.com is the first well-known AGPL-era SaaS to pull its codebase in 2026, and it cited AI-driven vulnerability discovery — not cloud-vendor parasitism — as the rationale. [The announcement](https://cal.com/blog/cal-com-goes-closed-source-why) immediately became a referendum on whether open source is still viable for commercial SaaS in the era of automated LLM code-auditing.

## Analogy

HashiCorp's BSL move, but the scapegoat is Claude Mythos instead of AWS.

## Why it's emerging now

On Apr 15, 2026, Cal.com relicensed its public repo as [Cal.diy](https://cal.com/blog/cal-diy-open-source-to-closed-source) (MIT, stripped of 13 feature categories) and anchored the move to Claude Mythos's one-shot discovery of a 27-year-old OpenBSD bug eight days earlier. The Hacker News thread (382 pts, 315+ comments) is dominated by skepticism — Simon Willison asked CEO Bailey Pumfleet if the message is 'we're not confident in our own ability to secure your data.'

## Related terms

- *child:* Cal.diy
- *competitor:* Calendly
- *competitor:* Easy!Appointments
- *related:* HashiCorp BSL
- *related:* Elastic license change
- *related:* Redis license change
- *related:* MongoDB SSPL
- *related:* AGPL-3.0
- *related:* Claude Mythos
- *parent:* source-available
- *parent:* commercial open source
- *related:* security through obscurity

## Sources

1. [Cal.com — Why we went closed source (announcement)](https://cal.com/blog/cal-com-goes-closed-source-why)
2. [Cal.com — Cal.diy: the technical transition](https://cal.com/blog/cal-diy-open-source-to-closed-source)
3. [Cal.com — Open source is collapsing under AI-powered threats (PRNewswire)](https://www.prnewswire.com/news-releases/open-source-is-collapsing-under-ai-powered-threats--calcom-302742216.html)
4. [The New Stack — Cal.com goes private: a security reckoning for open source](https://thenewstack.io/cal-com-codebase-security-ai/)
5. [byteiota — Cal.com Goes Closed Source: AI Security or Business Move?](https://byteiota.com/cal-com-goes-closed-source-ai-security-or-business-move/)
6. [implicator.ai — Cal.com Goes Private: Best Open Source Alternatives](https://www.implicator.ai/cal-com-goes-private-as-self-hosted-calendly-choices-narrow-in-2026/)
7. [BetaNews — Cal.com drops its open source model over AI threat concerns](https://betanews.com/article/cal-com-drops-its-open-source-model-over-ai-threat-concerns/)
8. [Hacker News discussion (382 points)](https://news.ycombinator.com/item?id=47780456)

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_Generated by EarlyTerms · https://earlyterms.com/term/cal-com_