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# Back-end developer

- **Company:** Apptweak
- **Location:** Brussel, Belgium
- **Experience:** Experienced
- **Contract:** Permanent contract
- **Skills:** Application Programming Interfaces (APIs), Amazon Web Services, Code Review, Databases, Extract Transform Load (ETL), Software Debugging, Github, Python (Programming Language), PostgreSQL, MongoDB, Online Analytical Processing, Open Source Technology, Queueing Systems, Ruby, TypeScript, ReactJS, Backend, Git, Kubernetes, Information Technology, Non-relational Database, Front End Software Development, Vertica, Docker, Web Api, Golang
- **Published:** November 12, 2026
- **Apply:** https://jobs.apptweak.com/o/backend-developer-5

## About the Role

o Bachelor or master's degree in computer science or engineering.
o 3+ years of experience working with databases, building data models and optimizing queries for performance at scale.
o Knowledge of relational (PostgreSQL) and non-relational databases (MongoDB)
o Knowledge of Docker.
o Proficiency in at least one backend language (Ruby, Python, Go…)
o Building and maintaining APIs or services, writing tests, Git and code review
o Debugging and monitoring live systems, handling incidents, and performance work beyond queries
Nice-to-have
o Experience with AWS and Kubernetes.
o Knowledge of OLAP databases (Clickhouse).
o GitHub profile or link to open source work - we'd like to see any project you're proud of (personal or professional).

## Description

We're looking for a motivated Back End Developer to join our team as we continue to scale.
You'll be responsible for helping us to bring AppTweak to the next level! For that, you will work in a multi-skilled team responsible for part of the AppTweak tool and infrastructure. You will take care of the development and maintenance of data fetch workers and our databases.
Under the direct supervision of the Engineering Manager, you'll work in a multidisciplinary squad (ASO Squad) alongside senior backend and frontend engineers and product designers. You'll also receive support from the Backend Chapter and Backend Tech Lead. This environment offers an excellent opportunity to learn from experienced colleagues, strengthen your technical skills, and grow as an engineer.
Location: Brussels, hybrid setting (min. 3 days per week at the office)., As a Back-end developer, we expect you to have a first understanding of the current tech environment and database structure.
In your role, you will help us make the right decisions by understanding business requirements and translating these into strong scalable solutions.
You will also take part in the systems implementation with the rest of your team.
Your focus will be on:
o Architecture and build scrapers and ETL pipelines that ingest the data that power AppTweak;
o Architecture and build API's that make those data available;
o Monitor and optimize our message queue systems;
o Monitor and optimize our databases., AppTweak welcomes applicants of every gender, age, background and identity. If you need any adjustment during the hiring process, just let us know.
[Please note you will need a Belgian valid visa/work permit to be eligible for the role].

Technologies we use
o We're mainly relying on three different languages:
# Ruby in the backend (for APIs and crawlers).
# Typescript in the frontend (for our React SPA).
# Python (mainly used by our Data Science team).
o Everything is hosted on AWS and running on K8s, and we have created a robust CI system to develop and deploy our code quickly.