Stefan Diskić

Senior Software Engineer

Complete software products, start to finish — frontend interfaces, backend systems, and the infrastructure that runs them.

Fundamentals first, AI to accelerate. I use Claude Code to ship faster — the engineering judgment behind it is what keeps things solid and secure.

Top Rated Plus on Upwork$100K+ earned
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stefan — senior software engineer
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featured work01 / 09

scroll to traverse the system map

01 Groute — Fleet Management SaaS
Co-Founder & Lead Engineer

Architecting a real-time GPS telemetry platform from zero to production — frontend, backend, ingestion pipeline, and the infrastructure it all runs on.

ReactNestJSBunRedisTimescaleDBCloudflare
Open case study →
02 Tortilla Casa — Multi-Store Ordering
Tech Lead

A complete web + mobile ordering platform for a multi-city fast-food franchise — and a sister pizza brand launched on the same foundation.

Next.jsStrapi CMSPostgreSQLReact Native
Open case study →
03 Charly Cares — Babysitting Platform
Cross-Platform Developer

Shipping features across web and mobile for the largest babysitting platform in the Netherlands — one codebase, every screen.

ReactReact Nativereact-native-webTypeScript
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04 Croptune — Agri-Tech Backend
Lead Backend Engineer

Owning the central API of a plant-nitrogen-estimation platform — and re-architecting a fragile codebase without stopping feature work.

Node.jsExpressMongoDBVue.js
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05 Gastrol — Gas Cylinder E-Commerce
Full-Stack Engineer

An online store for gas cylinders with two distinct storefronts — one for individual customers, one for businesses — built on Next.js, Payload CMS, and a type-safe tRPC API.

Next.jsPayload CMSMongoDBtRPC
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06 Bluestudio — Marketing Agency Site
Founder & Technical Lead

The site for my own digital agency — an animation-led showcase of our work and services, built with Next.js, Tailwind, GSAP, and Three.js.

Next.jsTailwindGSAPThree.js
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07 Convose — Interest-Based Chat
React Native Developer

Frontend for a mobile chat app connecting people by shared interests, in real time, across iOS and Android.

React Native
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08 Biblija NSP — Bible Reading App
Creator

A modern Serbian Bible translation existed only as a PDF. I turned it into structured data and built reading, highlighting, and search across web and mobile.

Next.jsPayload CMSReact NativeSQL
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09 Biblio — Offline-First Trivia
Creator

A Bible trivia game with multiple translations in local SQLite, three difficulty modes, and online multiplayer with shareable lobbies.

React NativeSQLiteFirebase
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about01

I build complete software products — frontend, backend, and the infrastructure they run on. Over the past 6+ years I've shipped real apps end to end, most recently as co-founder and lead engineer of Groute, a fleet-management SaaS built from the ground up.

I favor solid architecture, clean data, and maintainable code over whatever framework is trending. That's also why I lean on modern AI tooling — it lets me move faster without cutting corners on the fundamentals.

core stack02

Languages

TypeScriptJavaScriptPython

Frontend

ReactNext.jsAstroVueHTMLCSSTailwind

Mobile

React NativeExpo

Backend

Node.jsNestJSExpressRESTGraphQLSQL

Data

PostgreSQLTimescaleDBMongoDBRedis

Infra & Tooling

VPSCloudflareCI/CDClaude CodeGitAWS
experience05
Co-Founder & Lead Engineer
Groute · fleet-management startup
Jan 2026 — Present
Full-Stack Developer
Q Agency · Contract · Zagreb, Croatia · Remote
Mar 2024 — Present
Technical Lead
Bluestudio — Digital IT Agency · Novi Sad, Serbia
Dec 2023 — Present
Full-Stack Developer
Upwork · Freelance · Serbia · Remote
Jun 2020 — Present
Frontend Developer
Atessoft · Full-time · Niš, Serbia
Feb 2021 — Sep 2023
React Native / Mobile Developer
Convose · Contract · Berlin, Germany · Remote
May 2019 — Jun 2020
Frontend Developer
Coder Consulting International · Internship · Berlin
Nov 2018 — Sep 2019
testimonials06

Not curated quotes — screenshots straight off my Upwork profile, reviews and all.

Stefan’s Upwork profile: Top Rated Plus badge, 100% Job Success, $100K+ total earnings, 17 total jobs, 3,293 total hours
5-star Upwork review for "Video Recording Mobile App (iOS/Android)": "Stefan did awesome work and was great at bringing his own ideas to the app to make the project even better! Looking forward to our next contract."
5-star Upwork review for "Regex for React Component": "Stefan did a great job creating a form control component for a quick project. His code is clean and easy to understand. He communicates well and is very efficient. I look forward to working with him again on larger projects."
5-star Upwork review for "In need of a backend Javascript developer": "Stefan did a great job with everything we asked of him. He was efficient and flexible with what we needed. We look forward to working with him again!"
5-star Upwork review for "React Native Developer For New App": "Stefan was an absolute joy to work with! We had quite a few obstacles come underway as the project was developing, but he handled them smoothly and kept on performing way over expectations. I would 10/10 recommend stefan to anyone seeing to get some work done. Nice guy, deliveres on all deadlines and goes beyond what’s expected. Thanks Stefan!"
5-star Upwork review for "React Native + Firebase App developer": "Great to work with, highly recommended!"
5-star Upwork review for "Upgrade of existing React native app": "Thanks for your help, quick response time"

Let's build something.

Have a product to ship — or one that's stuck? Tell me about it and I'll give you an honest take on how I'd approach it.