data object
2025Ledger
An append-only event store with typed projections and time-travel queries. Powers reporting for a fintech back office.
KotlinPostgreSQLEvent sourcing
Available for select work · Remote · Europe
A finite set of
things, done exhaustively.
I build typed, dependable systems — backends, tooling and the quiet infrastructure that holds products together.
SealedClass.kt
1package dev.sealedclass2 3sealed interface SealedClass {4 val who = "Ivan — Software Engineer"5 6 data object About : SealedClass // who I am7 data object Work : SealedClass // what I've shipped8 data object Writing : SealedClass // what I've learned9 data object Contact : SealedClass // say hello10 11 // exhaustive — nothing else to handle.12}01data object About
About
A sealed class has a finite, known set of subtypes — the compiler can reason about all of them. I try to write software, and a career, the same way: a small set of things, each handled exhaustively.
I’m a software engineer focused on backend and systems work — the layers most users never see but always feel. I care about correctness, clear boundaries and code that’s still legible a year later.
My happy place is a strong type system, a fast feedback loop and a problem worth modelling well. I’ve shipped APIs, data pipelines and developer tools, and I like leaving things simpler than I found them.
Working set
Kotlin
TypeScript
Go
PostgreSQL
gRPC
Kafka
Docker
Kubernetes
AWS
Next.js
fun approach() = "simple, typed, tested"
02data object Work
Selected work
A few things I've designed and shipped. Each one a closed problem, modelled until it stopped surprising me.
data object
2024Relay
A self-hosted webhook gateway with retries, signing and a replay UI. Handles millions of deliveries a day.
GoKafkagRPC
data object
2024Sealed
A tiny CLI that turns API schemas into exhaustive, type-safe clients. The project that named this site.
TypeScriptCodegenOSS
03data object Writing
Writing
Notes on types, systems and the craft of keeping software boring.
data object Contact
Let’s seal something
worth building.
Have a problem that deserves a precise solution? I’m open to select freelance and full-time work.