Callstack is an AI-native engineering company. This GitHub organization is home to the open source projects we build, maintain, and use in production work across React and React Native apps serving hundreds of millions of users.

These repositories focus on the parts of delivery that have to hold up under real pressure: app architecture, performance, testing, observability, upgrades, native integrations, and the tooling teams need to ship faster without losing control.

We work in the open and maintain for the long term. That means production-ready libraries, clear documentation, active maintenance, and tools that solve real engineering problems instead of demo problems.

For earlier-stage and more experimental, future-facing work, visit Callstack Incubator.

• Sustainable open source: We maintain projects for the long haul. The libraries here are used in real products, tested in demanding environments, and built for teams that need stability. We fund OSS creators through GitHub Sponsors.
• Enterprise-grade tooling: We build for teams shipping any kind of software, from startups to Fortune 300 companies. That means stability, performance, observability, upgrades, testing, and the infrastructure around full SDLC.
• Developer experience/Agent experience: Good tools should get the job done, be delightful to use, fast, and not get in the way. This is how we build them. We care about clear docs, skills, sensible defaults, and workflows that help teams ship faster on tighter feedback loop.
• Open collaboration: We build in the open and want feedback early. Many of these projects come from real delivery work, then get shaped further through issues, contributions, and community input.

You can reach us in a few places:

• Join the conversation on Discord, where we have dedicated channels for individual projects.
• Follow updates at callstack.com/blog.
• For questions or enterprise support, contact: [email protected]