Jacek Leszczyński
Staff AI Software Engineer · Wrocław, Poland
Staff AI Software Engineer and tech lead on Bobsled's AI team. I take large
projects from spec to production — agentic backends, natural-language-to-SQL,
and the multi-cloud data platform underneath.
Contact
Skills
- Languages: TypeScript, Python, Java, Go, C# (.NET)
- Frontend: React, Next.js, Angular
- Backend & platform: Node.js, Spring Boot & Spring Cloud, microservices, Kubernetes
- AI: LangGraph / LangChain agents, natural-language-to-SQL, agentic RAG, evals
- Clouds: GCP, Azure, AWS, OCI (Oracle)
- Data: Snowflake, Databricks, BigQuery, DuckDB, PostgreSQL, CosmosDB
- Also: type-safe APIs (Zod), data visualisation (ECharts / Recharts), Ionic
Experience
Bobsled — Staff Software Engineer (Jun 2024 – Present)
Tech lead on the AI team, owning larger projects from spec through to production.
AI analytics product (natural-language-to-SQL): tech lead for Data Apps, an interactive
BI product with AI-generated dashboards on Next.js & React; built the Python agent
backend on LangGraph; added cross-source analytics with DuckDB across Snowflake, BigQuery
and Databricks; owned the charting layer (ECharts/Recharts); hardened embedded dashboards
(RS256 key isolation, origin allow-lists, rate limiting, revocable tokens).
Core data platform (Sledhouse): led the OCI Spark engine project on Oracle Data Flow;
reworked the customer-controlled backfill flow; built source connectors and ingestion
across the multi-cloud data plane.
Bobsled — Senior Software Engineer (Feb 2023 – Jun 2024)
Cross-cloud data-sharing platform: source connectors and ingestion (XML, latest-file
overwrite, SFTP), control-plane services, and SOC 2 continuous monitoring.
Fonoa — Senior Software Engineer (Sep 2021 – Dec 2022)
Lookup and Reporting products: microservices on Kubernetes in Node.js, C# (.NET 6) and Go.
QIAGEN — Software Development Lead (Apr 2021 – Sep 2021)
Led development and operations for a biotech product, recruited engineers, owned the roadmap.
QIAGEN — Senior Java Developer (Mar 2019 – Apr 2021)
Microservices with Spring Cloud; Azure services; IoT and Ionic mobile apps.
Sendit — Full-Stack Engineer (Jun 2016 – Mar 2019)
Built bliskapaczka.pl and sendit.pl (Angular, SSR, PWA), an embeddable parcel-shop map
widget, and a public REST/RPC API with OAuth 2.0.
Credit Suisse — System Engineer (Nov 2015 – Jul 2016)
Requirements analysis, system design, development (VB, Java, Oracle), third-line support.
Nokia Networks — Java Software Engineer (Sep 2014 – Nov 2015)
Test-automation framework, Eclipse RCP plugins, network-communication test backends.
Nokia Networks — Integration & Verification Engineer (Jan 2013 – Sep 2014)
Automated tests (Robot Framework), Jenkins pipelines, lab test beds, Python scripting.
Education
- Politechnika Wrocławska — MSc, Computer Science (2013 – 2016)
- Politechnika Wrocławska — BSc, Computer Science (2009 – 2013)