Jiří Kozlovský
Data Platform Engineer + DevOps/SRE (10+ years of XP)
I design, deploy and run data platforms, mostly on Kubernetes. I am available for B2B contracts, remote or in Brno.
Looking for a design partner
I have spent several months building a performant database in Zig. It is intended to scale to petabytes of data, to handle IoT streams as well as aid in high-frequency trading operations. Currently, it has several ASOF join algorithms, supports streaming Polars computations, supports reading Iceberg tables from an object storage, supports auto-scaling, has the option of running its own ingestion layer from Kafka (with Share Groups implementation), and many more features.
I am running it in production for over a month (as of Nov 2026), and would like to onboard an early business partner to test it on your own infrastructure. In return you shape the roadmap and get a discounted three-year license to run it (including upgrades & support).
My XP
I have worked for a client under NDA Since 2024.
- I replaced EMR and MSK with Spark and Kafka on our own Kubernetes clusters. The client saves over $75K a month. Both migrations went through without downtime or data loss, and the self-run Kafka on Strimzi has been more reliable than MSK.
- I help pick the engine for the workload. Often the right answer is no database at all, just Iceberg tables on object storage. Our own Trino clusters replaced Athena and made queries 3 to 20 times faster.
- I moved the client's teams from Terraform to ArgoCD and GitOps, which ended configuration drift.
- I wrote a Grafana data source plugin that drafts SQL with an LLM. It gives the model the error message, the dashboard variables, the Iceberg schema and a preview of the result. The client uses it heavily in production.
Before that I spent seven years at Seznam.cz, 2016–2023. I led the move of about 100 ETL jobs from YARN on bare metal to Kubernetes, and processing time and cost fell by about 60%. My master's thesis cut the HBase query latency of campaign statistics for large advertisers about 50 times, to about one second.
I am comfortable writing low-level code in C++, Rust and Zig as well as higher-level code in Scala, Python, Java, PHP and Go.
Open source
- ClickHouse #69712: Avro unions read and written as Variant, merged.
- ClickHouse Kafka Connect #368: Tuple and Variant support, merged.
- Terraform provider for Kubernetes #2573, merged.
- Trino #27641: the pull request that set off ASOF join support in Trino.
ClickHouse Certified Developer. MSc, Brno University of Technology. Czech and English.
Contact
Email b2b@jkozlovsky.cz with a few lines about what you are working on. I am also on LinkedIn and GitHub. I offer consulting services at €125/hr (before tax).