Mid-Level, Senior

Backend Developer (Freelance)

Woluwe-Saint-Pierre, Belgium · Hybrid

Passionate about tech, digital, and innovation? Join the 1,800 employees at Smile, the European leader in open-source integration, spread across 20 agencies in 9 countries. Collaborative spirit and knowledge sharing are at the heart of our DNA. Our experts push the boundaries of open source every day to build a smarter, more efficient, and more responsible digital world. Here, we don't just follow trends, we create them! ? Join Smile in Brussels and take part in projects that truly matter! ?

We are currently looking for a talented Backend Developer (Freelance) to join our dynamic team and work on high-impact projects for one of our major clients.

Position Overview

Status: Freelance
Location: Brussels, Belgium (Hybrid model: 2-3 days of remote work per week)

Your Responsibilities

As a Backend Developer, your daily missions will include:

Designing and developing robust, scalable, and high-performance backend APIs and microservices.
Ensuring code quality through rigorous testing (unit, integration) and continuous integration/continuous deployment (CI/CD) pipelines.
Collaborating closely with Frontend Developers, Product Owners, and DevOps engineers to deliver seamless digital solutions.
Optimizing applications for maximum speed, security, and scalability.
Troubleshooting and debugging production issues to maintain high system availability.
(For Senior profiles) Mentoring junior team members, driving technical architecture decisions, and championing best development practices.

Profile & Technical Skills

Strong experience in backend development using modern open-source languages and frameworks (e.g., Python, Node.js, Java, PHP, or Go).
Solid understanding of relational and non-relational databases (e.g., PostgreSQL, MySQL, MongoDB).
Familiarity with RESTful APIs, GraphQL, and microservices architecture.
Experience with cloud platforms (AWS, Azure, or GCP) and containerization (Docker, Kubernetes) is a strong asset.
Good understanding of Git, CI/CD tools, and agile methodologies (Scrum/Kanban).
Excellent problem-solving skills and a strong team spirit.
Language: Professional fluency in English. Knowledge of French or Dutch is a plus.

Why Smile?

Proximity Management: Our management by peers fosters open dialogue and the implementation of a tailored career path.
Continuous Learning: Because the digital sector is in constant motion, Smile is committed to making you an expert in your field, thanks to a comprehensive training offer: access to an e-learning platform, financing of certifications, and knowledge-sharing tools.
Vibrant Culture: Your year will be animated by group and agency events: annual convention, participation in trade fairs, summer party, and formal & informal afterworks.

? The Next Steps

First Contact: A phone call to discuss your aspirations and what we can offer you.
Meeting: An opportunity to get to know each other and explore your professional background.
Business Interview: A discussion with one of our experts to assess your technical skills and define your goals.

Is this role right for you?

Your agent will tell you — in seconds.

Sign up and I'll tell you right away how well Smile matches you — what you already have, and what's missing. Then I stay on it: I search for you and only write when I find something worth your time.

or use email