Backend · Full-stack · Available for freelance
I design and ship production microservice platforms.
Freelance engineer based in France. Python, Rust and TypeScript, from a single typed API to a 40-service mesh with realtime, billing and observability built in.
Selected work
What I build
A look at the kind of systems I take responsibility for end to end.
LeavePulse - SaaS platform
A ~40-service platform built single-handedly: a typed public BFF over a gRPC service mesh, hybrid RBAC/JWT auth, dual realtime websocket gateways, billing with payment-provider webhooks, and ClickHouse-backed observability.
- Typed public BFF (Litestar + msgspec) generating its own OpenAPI over an internal gRPC mesh
- Auth: hybrid RBAC + JWT/JWKS, Argon2id with peppering, Snowflake IDs, short-lived websocket handshake tokens
- Two realtime gateways (client + agent) with a Discord-style handshake and NATS JetStream fan-out
- Billing with merchant-API integration, webhooks, subscriptions and event-driven order lifecycle
- Cross-platform desktop launcher in Rust + Tauri 2 + Vue 3, with an xtask monorepo and Android target
- SDK-first: a public contract package with generated SDKs in Python, TypeScript and Rust
Multi-language SDK generator
A contract-first toolchain (in Rust) that reads the platform's OpenAPI specs and realtime manifest, builds an intermediate representation, and emits a typed, resource-object SDK for TypeScript, Python and Rust at once — plus a reference of the object graph.
- parser → IR → emitters: one source of truth, three idiomatic client libraries
- Fully automated pipeline (cargo xtask): snapshot, regenerate, publish to per-language repos — idempotent and offline
- Five auth methods (device flow, PATs, OAuth2 + PKCE, service tokens, cookie login) and a Nuxt transport with SSR cookies, CSRF and refresh-on-401
Service infrastructure toolkit
A public, reusable Python library that every backend service in the platform is built on — the shared layer for observability, gRPC, resilience and caching, so each service ships production-grade plumbing for free.
- Observability: Prometheus instrumentation, structured request-scoped logging, SQLAlchemy slow-query logging, OpenTelemetry tracing with OTLP auto-instrumentation
- gRPC helpers (shared channels, metrics/JWT/internal-token interceptors, error translation), Redis rate limiting and a TTL cache with in-flight dedup and Redis fallback
- Packaged with optional extras and CLI code generators — a real internal platform tool, not glue code
MagicUtils - Minecraft toolkit
A published, multi-platform Java/Kotlin library (300+ source files) with its own Maven repository and docs. The shared foundation other plugins build on — including the LeavePulse agent.
- One toolkit across Bukkit/Paper, BungeeCord, Velocity, Fabric and NeoForge
- Modular: config (YAML/TOML), commands (incl. Brigadier), localisation, HTTP clients, placeholders, logging
- Distributed via a self-hosted Maven repo under dev.ua.theroer with generated documentation
LeavePulse server agent
The on-server side of the platform: a multi-platform Minecraft agent (190+ Java files) that streams privacy-aware telemetry and whitelist events to the backend over HTTP and websockets.
- Bukkit/Paper, BungeeCord/Waterfall, Velocity, Fabric and NeoForge from a shared core
- Whitelist enforcement (kick/restrict), playtime tracking, in-game account linking
- Auto-update by channel with SHA-256 validation and Ed25519-signed manifests
Token-driven Vue UI kit
The component library this very site is built on: ~40 accessible Vue components, a runtime theme engine that re-skins everything from a JSON token set, built on Tailwind v4, reka-ui and motion-v.
- Runtime theming — themes are plain JSON, applied live to CSS variables
- Accessible primitives on reka-ui with tailwind-variants for typed styling
- Shipped as a versioned, tree-shakeable ESM package with generated types
Bots, scrapers & integrations
Telegram and Discord bots, scraping pipelines and service integrations — the fast, high-leverage work that automates a real process and pays for itself quickly.
- Async Python services and bots with clean deploy stories
- Third-party API integrations and webhook processing
- Data pipelines and scheduled jobs
Stack
Tools I reach for
Backend
- Python
- FastAPI
- Litestar
- gRPC
- msgspec
- SQLAlchemy 2.0
Frontend
- TypeScript
- Vue 3
- Nuxt
- Tailwind v4
- Tauri
Systems & infra
- Rust
- Java
- Kotlin
- Docker
- GitHub Actions
- GHCR
Data & realtime
- PostgreSQL
- Redis
- ClickHouse
- NATS JetStream
- Prometheus
How I can help
Ways to work with me
Backend & APIs
FastAPI / Litestar services, gRPC meshes, auth, billing — designed to run in production, not just demos.
Bots & automation
Telegram/Discord bots, scrapers, integrations and scripts that take a manual process off your plate.
Web & full-stack
Nuxt / Vue / TypeScript front-ends and full-stack features, wired to a backend that holds up.
Rescue & review
Audit, debug or finish an existing codebase — Python, Rust or TypeScript.
Contact
Let's talk about your project
Tell me what you need built. I usually reply within a few hours.