COSS Weekly: Cal.com Goes Closed Source, Mistral Borrows $830M for Data Centers, OpenAI Acquires Promptfoo, and more

Sabir Ibrahim — Mon, 20 Apr 2026 22:15:45 +0000

This week in COSS: Mistral raised $830 million in debt financing for AI data center expansion, OpenAI acquired Promptfoo signaling a growing focus on AI security, and Cal.com made waves by going closed source in a move that sparked debate about the future of open source software security. Self-hosted AI automation stacks featuring n8n, Dify, and Ollama are gaining traction, while PrestaShop announced a formal collective restructuring process and Starburst unveiled an AI-powered front end aimed at replacing conventional BI dashboards. We also feature the following companies in Cossmology: ACI.dev, Beanbag, Builderz, Cachix, Code Machine, DataChain, Flox, HTTPie, Manticore Software, and Redgate Software.

Featured COSS Companies

Redgate Software
Database DevOps tools and solutions

Manticore Software
Open-source fast database for search

Cachix
Nix binary cache hosting service

Builderz
AI agents & blockchain dev agency

ACI.dev
AI tooling governance platform

DataChain
AI data warehouse for unstructured data

Beanbag
Open source code review tools for teams

Code Machine
Multi-agent AI coding orchestrator

HTTPie
Human-friendly API testing tools

Flox
Reproducible dev environments built on Nix

More COSS Companies →

DEV Community: Sabir Ibrahim

COSS Weekly: Cal.com Goes Closed Source, Mistral Borrows $830M for Data Centers, OpenAI Acquires Promptfoo, and more

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Cal.com goes closed source: A security reckoning for OSS

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