Open to backend roles · remote or relocation Belgrade —:— CET · overlaps most of Europe

Backend systems, built to stay up.

I'm Marko Keser, a backend engineer working in C#/.NET and Java. I've shipped software that real businesses depend on daily, kept a US client's production app stable, and written the math models behind licensed slot games.

markokeser.dev@gmail.com LinkedIn GitHub
Running right now 3 services
restaurant-ops In production Open ↗
Full restaurant management system. Real staff use it to run their shifts.
ASP.NET Core · EF Core · MySQL · React · JWT
recruiter-scanner Public demo Open ↗
Scores recruiter matches and drafts the outreach message, in four tones.
ASP.NET Core MVC · C# · LLM APIs · JavaScript
kesermarko.com This page
Server-rendered, no framework, one stylesheet. The assistant below runs on my own endpoint.
ASP.NET Core · Razor · vanilla JS

Both links open the running app, not a screenshot.

Selected work

Two systems, both built solo — schema, API, auth, front end, deploy.

Restaurant management system

Solo build
Shipped 2024 · in production

Restaurants were running orders, menus and stock on paper and spreadsheets. I built the whole system — database schema, API, roles and permissions, and the interface staff actually touch — then deployed it. It has been in daily use since.

What's in it
  • Role-based auth so waiters, kitchen and owners each see only their own view
  • Order flow from table to kitchen, with live status
  • Menu and inventory management the owner can edit without me
  • Deployed and maintained on Railway, including migrations against live data
Stack
C#ASP.NET Core Entity FrameworkMySQL ReactJWT
Hardest part

Changing a schema that a business is already depending on. Every migration had to run without losing a night of orders.

Open the app Source

Recruiter scanner

Solo build
2025 · public demo

Job hunting meant writing the same message a hundred times. This reads a batch of recruiter listings, scores how well each one matches, and drafts the email or LinkedIn note — so the only manual step is deciding whether to send it.

What's in it
  • Four tones — professional, enthusiastic, exploratory, humble — from one profile
  • Batch generation across a whole list, with progress you can watch
  • Filters by match score, location and whether a LinkedIn profile exists
  • Copy, download as .txt, or send straight from the app
Stack
C#ASP.NET Core MVC LLM APIsJavaScript Razor
Hardest part

Getting reliable structured output from a model. The interesting work was in prompt design and in validating every response before it reached the UI.

Try the demo Source

Smaller experiments and one-offs live on GitHub.

Browse all repositories ↗

Durations calculate themselves from the dates, so this page never goes stale.

Where I've worked

Three roles across gaming, enterprise consulting and the Salesforce ecosystem.

Feb — Oct 2025 9 months

Backend / math developer

Wicked Games
  • Designed the logic and mathematical models behind online slot games — the rules that decide outcomes and payout behaviour
  • Kept every model inside the legal limits regulators check for, while keeping the game good to play
  • Backend work in Java on the platform that runs the games
Jan — Dec 2024 1 year

Backend developer

Quadro Consulting
  • Built features in Java for enterprise software and wired separate system components together
  • Moved onto a US client's C# web app — debugging, fixing and keeping production stable
  • Worked across the whole stack when the ticket needed it: C#, Java, JavaScript, HTML
Sep 2022 — Feb 2023 6 months

Salesforce developer, internship

Kameleon Solutions
  • Built components for client Salesforce orgs alongside senior developers
  • Handled both development and admin work inside the Salesforce ecosystem

Total time employed as an engineer: 2 years 3 months · recalculated on every page load

No percentage bars. Those measure nothing.

What I work with

Honest tiers. The first group is what I reach for without thinking.

Daily shipped production code with these
C#.NETASP.NET Core JavaEntity Framework SQLMySQLREST APIs Git
Comfortable used on real projects
JavaScriptTypeScriptReact SQL ServerPostgreSQL JWT / authClean architecture RazorSalesforce / Apex
AI work integration, not model training
LLM API integrationPrompt design Structured output + validationRetry / fallback handling
Also picked up as needed
Node.jsRedisRailway Probability modellingRegulatory compliance
Languages human ones
Serbian — nativeEnglish — fluentSpanish — learning

It's a model reading my CV. Verify anything important with me.

Ask about my work

Faster than reading the whole page. It knows my roles, projects and stack.

assistant ready
ai

Ask me anything about Marko's experience, projects or stack. I'll keep it short.

Email is fastest. I reply to everything.

Got a backend problem? Let's talk.

I'm looking for backend or AI-integration work — remote from Belgrade, or relocating for the right role. Tell me what you're building and I'll tell you straight whether I'm the right fit.

Email markokeser.dev@gmail.com Write ↗ LinkedIn in/kesermarko Open ↗ GitHub github.com/markokeser Open ↗ Phone RS +381 63 218 039 Call ↗ Phone ES +34 663 674 671 Call ↗