MarceliGrabowski
I help teams regain control over complex backend, cloud and legacy systems.
Hands-on backend/cloud engineer focused on pragmatic architecture, legacy modernization, Kotlin/Java systems and cloud-native platforms.
What I work on
Legacy system takeover
Build a working model of poorly documented or vendor-built systems before deciding what to change.
Backend and cloud modernization
Modernize incrementally when it reduces cost, risk, complexity or operational friction.
Kotlin/Java backend systems
Work mainly with Kotlin/Java, Spring Boot, Ktor, PostgreSQL and data-heavy integrations.
Cloud cost, performance and operational risk
Diagnose workload behavior, runtime constraints and operational hot spots before changing architecture.
IoT and connected-device platforms
Backend/cloud services for connected-device platforms, telemetry and smart energy workflows.
Identity and authentication complexity
Untangle authentication flows, platform constraints and operational edge cases.
Pragmatic technical leadership
Connect code-level facts, platform constraints and stakeholder decisions.
How I work
I usually start by building a real operating model of the system — not just reading documentation.
I treat documentation as an input, validate assumptions through code, logs, metrics, POCs and conversations with the team, then turn findings into practical next steps.
Good fit problems
I work best when a system is complex, poorly documented and important enough that guessing is expensive.
A system is hard to understand and the documentation is unreliable.
A team needs to take over a legacy or vendor-built system.
Cloud costs, performance or operational risks are becoming painful.
A backend or platform decision needs to be made with incomplete information.
A product needs pragmatic modernization without a rewrite fantasy.
A team needs someone who can connect code, platform constraints and stakeholder decisions.
Less interested in
Architecture for architecture’s sake, clean-code rituals without a clear operational benefit, or feature delivery without product and system context.
Technical notes
Longer technical notes live on a separate site, connected back here. They are for system takeover, pragmatic architecture, cloud platforms and decision-making.
Technical notesHow I build an operating model during legacy system takeover
POC is a decision tool, not a toy
Cloud cost investigation without guessing
Kotlin + GraalVM for serverless backend: when it makes sense
Contact
If this sounds like the kind of system, migration or technical decision you are dealing with, send me a short note.