TSM / CETIN
Senior backend and integration work on Kotlin/Java/Spring services, PostgreSQL-backed systems, B2B flows, PEW, NIP, change management and production rollout of new platform versions.
Senior Backend & Integration Engineer
Pavel Kleisner
Backend, integrations and releases — the unglamorous part where systems meet real data and have to stay up.
I work on Kotlin/Java/Spring services and PostgreSQL, mostly around TSM/CETIN production flow: B2B behaviour, data compatibility, incident analysis and rolling out new platform versions. I'd rather fix production than be right about it.
Primary stack
Kotlin · Java · Spring
PostgreSQL, Kafka-style messaging
Production rollouts
TSM 1.5 · 2.2 · 2.4
Lead on 2.2 / 2.4, core contributor on 1.5
Experience
9+ years
Backend, integrations, full-stack stints
Based in
Prague · CET
Open to remote collaboration
Where I fit best
Usually the value isn't another abstraction layer. It's a change that survives real data, integrations, support and the next release.
Integrations
B2B APIs, process flows, message behavior, retries, logs and failure modes that only become visible after deployment.
Releases
Rolling new versions into real environments while watching compatibility, old data and operational risk.
Architecture
Small safe changes, clearly named rules and service boundaries. No ceremony around patterns.
Debugging
Incidents through logs, metrics, databases and domain context. Not random patches around symptoms.
War story · anonymised
The UUID that wasn't a UUID
When we rolled out the first platform version, the integration spec said the
messageId would be a UUID. One partner started failing immediately.
Their system was quietly parsing the ticket ID out of the old
ticketId_timestamp format — even though the ticket ID sat right
there in the message body.
The clean fix was on their side, but in a corporate setting that change would take months. So I adapted our side back to the old shape and kept production running. Sometimes the right call isn't the pure one — it's the one that doesn't break someone else at 2 a.m.
Core stack
Primary
Kotlin Java Spring PostgreSQL Kafka
Also
Kubernetes Oracle Angular Python / Django Astro TypeScript
Experience snapshot
Most of my professional work is internal or client-owned, so I describe responsibility and production context rather than exposing code.
MNCP
Kotlin/Spring, Angular and database work around authentication, measuring batches, archives, exports and operational fixes.
ZIS
Enterprise Java and ZK/ZUL work across screens, controllers, services, DAO layers, imports, Excel processing and production bug fixes.
Interested in collaboration?
If you need a senior engineer for backend systems, integrations, production releases or long-term product development, email is the fastest channel.