Callstack is a React and React Native consultancy that builds and improves cross-platform mobile and web apps, and contributes heavily to the React Native open-source ecosystem. It now also offers what it calls agentic delivery, using AI agents in its engineering work.
The company has contributed to open source since 2016 and says it grew beyond 200 people in 2024. Callstack.io Sp. z o.o. is registered at Prosta 36 in Wroclaw, Poland, and its site states ISO 27001 certification. Buyers can email the sales team.
