JJobsSonar

Junior Full-Stack Developer (TypeScript / React ・ Supabase / Postgres)

KFS GROUP · Budapest, Budapest, Hungary

Full Stack EngineeringHybrid

About this role

This role is for an early-career engineer to build product features end-to-end, covering database, API, and React UI. You will work in a small, senior-led team using an AI-native workflow with tools like Cursor, Copilot, and Claude. The technical stack includes TypeScript, Python, React, Next.js, Tailwind CSS, and Supabase (Postgres). The position offers real ownership and mentorship, with the ability to ship to production within your first weeks. The role is based in Hungary with hybrid flexibility.

Skills & technologies

Nice to have

  • Firebase
  • UI/UX
  • GitHub portfolio

Read full description

Location: Hungary Type: Full-time or working student / part-time - both welcome Level: Junior ・ Working student ・ Recent graduate


Why this role


We build software that real businesses run on. You'll join a small, senior team where you own real features early ― not tickets that someone pre-chewed for you. You'll learn fast, ship to production within your first weeks, and have a senior engineer in your corner the whole way.


This is a role for someone early in their career who thinks in systems, not just syntax.


Let's be honest about AI (please read this)


We don't expect you to hand-type every line from memory, and we don't want you to. Of course you'll use Cursor, Copilot, Claude, and whatever comes next ― that's not cheating, that's the job in 2026. We want you to vibe-code.


But here's the thing the tools can't do for you: they don't know what the right answer is. We hire for that. Our focus is architecture and judgment ― the ability to decide what should be built, how the data should be shaped, where a responsibility belongs, and whether the code the AI just generated is actually correct, secure, and maintainable, or just plausible-looking.


So the bar isn't "can you write a for-loop without help." The bar is: do you understand the system well enough to steer the tools and recognize a good result when you see one? If you're early in your career but you genuinely _get_how the pieces fit together, you're exactly who we're looking for.


Tasks

What you'll do


Build product features end to end with AI-assisted tooling: database → API → React UI.


Learn to model data properly in Postgres ― schema, relationships, migrations, and Supabase Row-Level Security ― and understand why it's structured that way.


Build clean, usable interfaces in React + TypeScript.


Read, question, and improve the code you and the tools produce ― and learn to tell solid architecture from a shortcut that'll hurt later.


Grow quickly with real mentorship, code reviews, and ownership.


Our stack (what you'll learn on the job)


Languages: TypeScript, Python


Frontend: React, [Next.js / Vite], Tailwind CSS


Backend / Data: Supabase (Postgres, Auth, Storage, Edge Functions), SQL, RLS


Tooling: Git/GitHub, CI/CD, Claudflare, and the AI dev tools you already use


AI-native workflow: Cursor / Copilot / Claude as a normal part of how we build


Sysops: Debian, terminal, etc


You won't know all of this on day one. No junior does. You'll learn it here.


Requirements

What we're looking for


Must-haves


A real foundation in TypeScript / JavaScript and React ― through study, side projects, an internship, or things you've built for fun.


Architectural curiosity: you care why code is structured a certain way, not just whether it runs.


Basic comfort with SQL / relational data ― or the clear ability to pick it up fast.


You use AI dev tools well and critically ― you don't blindly paste whatever they output.


You communicate clearly in English and you're genuinely eager to learn.


Based in Hungary, or able to work reliably within CET hours.


Nice-to-haves


A GitHub or portfolio with something you actually built - however small or messy.


Exposure to Supabase, Firebase, or any Postgres-backed app.


An eye for UI/UX.


Currently studying computer science or similar (working-student arrangement very welcome).


German or another European language (not required ― English is our working language).


We care far more about how you think than about your CV length.


Benefits

How we work


Small team ― you learn directly from people who've shipped a lot, and your work matters from week one.


Hybrid: a real office in HU plus flexibility to work from home most of the week.


Student-friendly: flexible hours; we'll work around your lectures and exams.


Low bureaucracy: clear ownership, short feedback loops, no death-by-process.


What we offer


Fair junior compensation with clear room to grow.


Real mentorship ― not "figure it out alone."


Modern hardware and the AI tooling you need.


A learning budget for courses, books, and conferences.


The chance to grow into a serious engineer on a product that real customers use.


How to apply


Send a short note about yourself plus your GitHub / portfolio / LinkedIn. Built something you're proud of ― or even something broken you learned from? Link it. A CV is welcome, but what you've made and how you think tells us more.


No essay required. We review every application and reply to everyone.

Ready to apply?Apply now

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