Tomasz Jarosz

Software engineer · agentic development

Tomasz Jarosz

I build production software with AI agents in the loop, and the guardrails that make it safe.

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What I’m building

Products I design, build and operate on my own, end to end.

Launching early 2027 · Polish market

Trasownik

Route planner for gravel cyclists

Plan a ride on the map, check surfaces and climbs before setting off, and send the GPX straight to a bike computer: free, with no account needed. I co-plan my own rides with an LLM through a private MCP server.

Rust (axum) · React · PostgreSQL · self-hosted BRouter

In active development · public release Q2 2027

Agent Workbench

Coordination layer for parallel AI coding agents

Lets several Claude Code and Codex sessions work side by side without losing track: a live view of what each agent is doing and what needs my decision, a task register the agents read and update themselves, an isolated git worktree per task, and tests and builds offloaded to a dedicated build server.

Python · Claude Code & Codex hooks · git worktrees

I build the guardrails for agentic work myself: agent code review, staged releases that ship only what passed, persistent project memory and quality gates.

Over a decade of shipping software, from ML-driven airline pricing at Sabre to regulatory reporting at UBS. Today I work as a contract engineer on a high-traffic platform and build my own products end to end.

Experience

  1. Mar 2026 – now

    Senior Software Engineer · Independent contractor

    Product engineering on a high-traffic platform, with AI coding agents in every task.

    • Fine-tuned a 35B Qwen vision-language model with LoRA for content moderation and built the evaluation harness that picked the production model: 94.6% recall at 99.9% precision.
    • Benchmarked and rewrote hot SQL queries: keyset paging, index-served ordering, caching.
    • Shipped product features end to end in a large legacy PHP codebase, from the data model and search-backed listings to the frontend.

  2. Aug 2022 – Jun 2026

    Senior Software Engineer · UBS

    Regulatory exposure reporting and ledger services in a bank.

    • Built a new regulatory exposure reporting application (Java 21, React, Azure Functions), end to end.
    • Moved complex Sybase stored procedures into tested Java services, so core calculations became reviewable and safe to change.

  3. Jan – Feb 2024

    Developer Track · Hong Kong PolyU · Polkadot Blockchain Academy

    Four weeks full time of Rust, Substrate and blockchain engineering, taught by Parity and Web3 Foundation engineers.

    • Excellence certificates in Substrate (top 10 of ~30) and FRAME (top 16 of ~30).
    • Capstone: a Uniswap v2-style AMM DEX built as FRAME pallets on a custom parachain.

    Substrate certificateFRAME certificateGraduation

  4. Oct 2019 – Aug 2022

    Senior Software Engineer · Sabre

    An ML pricing platform for airlines (incl. Etihad): demand forecasting and price optimisation.

    • Data pipelines in Python and Spark on AWS EMR, services in Java/Spring, UIs in React; moved the analytical workload from MongoDB to an OLAP-style model.

  5. Jan – Oct 2019

    Java Software Engineer · Ocado Technology

    Oracle → PostgreSQL and GWT → React migrations of a call-centre application.

  6. Jun 2015 – Dec 2018

    Intern → Mid Java Developer · Sabre

    Spring Batch pipelines and internal tools for airline fare and tax data.

  7. Mar 2013 – Jun 2015

    Web Developer · AstroMedia

    WordPress sites and a JavaScript content-aggregation tool, plus SEO and AdWords campaigns.

Tools

AI
Claude Code, Codex, MCP servers, Multi-agent review, LoRA fine-tuning, LLM evaluation
Backend
Rust (axum), Java, Spring Boot, Python, PHP
Frontend
React, TypeScript
Infrastructure
Linux, nginx, Docker, AWS, Azure
Data
PostgreSQL, MariaDB, Spark, Oracle
Blockchain
Substrate, Solidity

Applied Computer Science, Krakow University of Economics, 2013 – 2019