marius@fitthebit — zsh

❯whoami
Senior backend engineer — Java, Spring Boot, Kafka
❯cat now.txt
Building ING Bank's KYC onboarding platform — ~2,500 journeys/day.
❯

Hi, I'm Marius.

I design and operate banking-grade backend systems — and I enjoy explaining how they work.

Download CV Get in touch

cluj-napoca, ro · open to full-time & b2b

$ cat about.md

About

For the past 8+ years I've been building and running distributed systems in Java. Right now that means the KYC onboarding platform at ING Bank, where roughly 2,500 customer journeys a day flow through services my team designs, ships, and keeps healthy across two datacenters.

I care about the unglamorous parts of engineering: schema compatibility, observability, the migration plan, the incident at 2 a.m. and the honest postmortem after it. I mentor junior engineers, review a lot of code, and use Claude and Claude Code daily — with judgment.

Outside the day job I run a guesthouse platform I built from scratch (in production since 2019), and I've taught at my alma mater.

LOCATION

Cluj-Napoca, Romania

LANGUAGES

Romanian — native · English — C1

CURRENTLY

KYC onboarding platform @ ING Bank

AVAILABILITY

Open to full-time roles and B2B collaborations.

$ ls -lt ~/experience

Where I've worked

Senior engineer on the microservices platform orchestrating ING Bank's end-to-end KYC onboarding flow — roughly 2,500 customer onboarding attempts per day on an active-active deployment (4 instances across 2 datacenters).

Designed and implemented the Kafka-based event pipeline that orchestrates all downstream calls after customer consent — Avro serialization with a Schema Registry for contract management.

Led a full system migration to a new infrastructure stack — application cluster, Oracle database, Kafka topics, firewall rules, and codebase — coordinating the end-to-end cutover (~2 hours of planned downtime).

Owned the technical decision for the consent approval callback design during a migration between two consent management systems.

Resolved a critical production incident caused by a null-vs-empty list mismatch between two service versions running concurrently during rolling deployments.

Cut SELECT latency on high-volume tables by introducing targeted database indexes.

Mentored 3–4 junior engineers through pairing, design discussions, and structured code reviews; consistently active in code review across the team.

JavaSpring BootApache KafkaAvro + Schema RegistryOracleREST / OpenAPIJUnitMockitoMavenDockerOpenShiftAzure PipelinesPrometheusGrafana (Tempo, Mimir, Loki)

$ ls ~/projects

Things I run

In production2018 – present

Pensiunea Steaua Apusenilor — property management platform

Full-stack booking and property-management platform built and operated for a family-run guesthouse in the Apuseni mountains. Started as my Bachelor's thesis, then redesigned into a production-grade system with major upgrades to architecture, stack, and feature set.

Multi-property support — several guesthouses managed from a single backend.

Multi-language frontend with text and images editable on the fly through authenticated REST endpoints — no redeploys for content changes.

End-to-end reservation management: availability, booking workflows, email notifications.

Calendar synchronization with external booking platforms (e.g. Booking.com).

Authentication and authorization with Keycloak.

Self-managed deployment on a VPS — full ownership of infrastructure, HTTPS, and routing.

JavaSpring BootAngularPostgreSQLKeycloakNGINXDockerLinux (VPS)REST APIs

steauaapusenilor.ro ↗

Master's dissertation2020 – 2021

Automated code evaluation & plagiarism detection

Jenkins-based evaluation platform orchestrating automated testing of student submissions across multiple Git repositories — aggregated statistics, scoring metrics, and plagiarism reports. Built so teaching staff can grade laboratory and exam work objectively, repeatably, and at scale.

JavaSpring BootAngularJenkinsGit

$ grep -r ~/skills

What I work with

Languages

JavaJavaScriptTypeScriptSQL

Backend

Spring BootSpring (MVC, Data, Security, AOP)REST APIsMicroservicesEvent-driven architectureOpenAPI / Swagger

Messaging

Apache KafkaApache AvroSchema Registry

Databases

OraclePostgreSQLMySQL

DevOps & cloud

DockerOpenShiftAzure PipelinesJenkinsNGINXLinuxAWS

Observability

PrometheusGrafanaLokiTempoMimir

Testing

JUnitMockitoTDDIntegration testingRegression testing

Frontend

AngularTypeScriptHTMLCSS

Auth

Keycloak (IDM)OAuth / OIDC

AI workflow

ClaudeClaude CodeAI-assisted developmentLLM API integration

Tools & practices

MavenGitIntelliJ IDEAAgile / ScrumCode reviewMentoring

$ cat education.log

Education & credentials

Oct 2019 – Jul 2021

Master's degree

Applied Informatics in Engineering of Complex Systems

Technical University of Cluj-Napoca

Oct 2015 – Jun 2019

Bachelor's degree (Engineer)

Automation and Applied Informatics

Technical University of Cluj-Napoca

CERTIFICATIONSPEGA — Certified Senior System Architect (CSSA)PEGA — Certified System Architect (CSA)ANC (Romania) — Authorized Trainer (Formator)

B2B → FIT THE BIT S.R.L.

B2B work runs through my company, FIT THE BIT S.R.L. — a one-engineer consultancy for complex backend systems.

Open to full-time roles and B2B collaborations.

$ echo "hello"

Get in touch

Hiring for a senior backend role, or need a complex system built and run properly? Write me — I answer every serious message, usually within a day.

Email me

linkedin ↗github ↗

Your data is used only to reply to you — privacy note.