Senior AI System Engineer

Piotr Miłkowski

Piotr Miłkowski

Piotr is a scientist-programmer with more than 15 years of software development experience. His background spans programming, software architecture, information systems specification, project management, and team leadership. Since 2018, he has focused on machine learning, with a particular emphasis on natural language processing since 2019, alongside publishing research presented at top-tier international conferences.

Piotr is a scientist-programmer with more than 15 years of software development experience. His background spans programming, software architecture, information systems specification, project management, and team leadership.

Since 2018, he has focused on machine learning, with a particular emphasis on natural language processing since 2019, alongside publishing research presented at top-tier international conferences.

What I’ve been shipping

Article
10/1/2026

Apex Is Now Generally Available: Agentic Coding Model for Mobile and Web, Specialized in React

Apex is now publicly available. Explore Callstack’s coding model for React Native and Next.js, with API pricing, benchmarks, and self-hosting options.
Event Cover
Webinar
7/21/2026

Behavior Review for AI-Native Delivery

AI can increase code output faster than teams can verify the real app. See why behavior review matters before merge.
Event Cover
Live Stream
7/16/2026

How to Teach Your Own AI Model, Part 2: What Should You Build First?

Explore practical AI model training, from choosing a first project and preparing data to fine-tuning locally and evaluating synthetic data.
Event Cover
Live Stream
6/18/2026

Training AI Is More Than Feeding It the Internet

A Live Stream with Kewin Wereszczyński and Piotr Miłkowski on AI training, datasets, tokenization, alignment, and why models infer patterns rather than understand meaning.
Article Cover
Article
6/5/2026

Optimizing Self-Hosted Gemma for Production Inference

How we optimized self-hosted Gemma 4 31B from baseline serving to 2.48x higher output-token throughput in production inference.
Article Cover
Article
5/27/2026

Introducing Apex: A Fast, Specialized Model for React Native

Apex is our new coding model designed for React Native. It achieves frontier coding results for mobile workflows at a fraction of the cost.
Event Cover
Live Stream
3/12/2026

React Native Evals: Measuring AI Code Quality in Practice

React Native Evals introduces a data-driven way to measure how AI coding models perform on real React Native development tasks.
Article Cover
Article
3/5/2026

Announcing React Native Evals

We built an open-source benchmark to measure how AI coding models handle real React Native tasks, such as animations, async state, navigation, and more.

JOIN US

Build the AI-native React Native future

Work with engineers who contribute to the ecosystem and turn new technology into real products. At Callstack, AI is part of how we build, learn, and ship software.

Join UsAbout us