Senior Software Engineer – PHP, TypeScript, Node.js

Stellenbeschreibung:

As part of the team you build new features
Solve scaling problems and take responsibility for entire projects — from the idea to reliable operation
We are looking for people who do more than just work through tickets: who understand systems, improve them, and actively help shape the e-invoicing landscape
You develop backend features with PHP 8.x and Symfony: domain logic, APIs and interfaces in a data-heavy codebase that has evolved over 18+ years
You work on the frontend with TypeScript, React and TanStack on modern UIs and production-focused workflows
You develop Node.js services for selected areas of our platform using TypeScript and Next.js
You work on JVM microservices with Java and Kotlin in the e-invoicing domain
You migrate data, refactor existing modules and modernize legacy PHP areas step by step in a clean way
You delve deep into error analysis and debugging when systems don’t behave as expected
You use AI as a real productivity lever
Depending on the topic, you also work on infrastructure and local dockerized development environments

You bring deep PHP/Symfony experience
You are proficient in TypeScript
You are eager to take on responsibility like a founding engineer
Comfortable working with multiple programming languages is important for this role
You have deep, independent expertise in software development with PHP and Symfony at a senior level — with clean domain design, testing and performance experience in a large, long-lived codebase
Depending on focus, you also bring TypeScript/React experience
You are confident with relational databases such as MySQL, including query optimization and data modeling for large datasets
Bonus: Experience with Node.js, data structures & algorithms, distributed systems and data-heavy applications
Bonus: Experience with JVM languages such as Java or Kotlin
Bonus: Open-source contributions or public projects on GitHub
You speak fluent German and have good English skills