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Jeremy.

Open to new projects

Cologne

Freelance Web Developer — Cologne · remote across DE & EU

Jeremy Thelen

I build web apps, backends and admin panels with PHP & Symfony – clean, fast and easy to maintain.

Start a project GitHub (opens in a new tab)

What I build

From the first idea to running in production – all from one person.

  1. Web app development

    Custom web applications with Symfony – from data model to interface.

    Technologies: Symfony · Twig · JavaScript

  2. Backend & REST APIs

    Clean interfaces that connect your systems reliably.

    Technologies: REST · PHP · SQL

  3. Admin panels with Symfony

    Back offices that let your team manage content and data on their own.

    Technologies: Symfony · Twig · Doctrine

  4. Maintenance & evolution

    Taking over existing PHP projects: fixing bugs, updating, shipping features.

    Technologies: Refactoring · Updates · Bugfixing

My toolkit

Focused on PHP & Symfony – plus everything that keeps a project stable.

backend/ Backend

  • PHP
  • Symfony
  • Doctrine ORM
  • REST-APIs

frontend/ Frontend

  • JavaScript
  • Next.js
  • Twig
  • HTML
  • CSS

databases/ Databases

  • MySQL
  • PostgreSQL

devops/ DevOps & tools

  • Docker
  • Git
  • Linux

languages/ Other languages

  • Python
  • Java

Selected work

01 / Personal project · e-commerce

SymfoShop

Challenge
A shop needs more than product pages: checkout, payments, taxes, invoices and a back office.
Solution
E-commerce on Symfony 7.4 with Stripe & PayPal, PDF invoices, an admin back office and a REST API – in German, English and French.

Technologies: Symfony · Doctrine · Messenger · Stripe · PayPal · Tailwind CSS · Alpine.js · OpenAPI

Code (opens in a new tab)

02 / Community project · library

Live in production

FrenchyBook

Challenge
A reading group in Cologne lends books to each other – but who has which one right now?
Solution
A shared library web app: barcode scanning on your phone, loans, waiting list and reminders – in German & French.

Technologies: Symfony · Doctrine · Turbo · Stimulus · AssetMapper · SQLite · Web Push

Live (opens in a new tab) Code (opens in a new tab)

Where I’ve been

  1. to

    Software development intern

    Internship

    Wissberg Dynamics GmbH

    PHP & AL, automated tests, documentation and customer support.

  2. to

    IT intern

    Internship

    Fornatis Deutschland GmbH

    Setting up workstations and hardware.

  3. to

    Apprentice application developer

    Apprenticeship

    Floyt Mobility GmbH

    Extended the Symfony admin backend and fixed bugs. Final project: a radius search.

  4. to

    Apprentice application developer

    Apprenticeship

    Gjuce GmbH

    Backend modules, SQL, REST APIs and dashboards for shop statistics.

Hi, I’m Jeremy.

Portrait of Jeremy Thelen
[PLACEHOLDER] Photo coming soon

IHK-certified application developer and freelance web developer based in Cologne.

My focus: Symfony backends, admin panels and APIs. Code should still make sense tomorrow – with clear structure, tests and docs.

On the side I’m training as an IT security specialist (IHK), followed by a Bachelor Professional in IT from 11/2026.

Location
Cologne · remote across DE & EU
Languages
German, French, English (C1)
Degree
IHK-certified application developer
Currently
IT security (IHK) → Bachelor Professional

Let’s talk.

Tell me briefly about your project – I’ll get back to you soon.

Email me directly

jeremythelen07@gmail.com
Rather talk in person? Book a short intro call.

I only use your details to reply. More in the privacy policy.