API/SOA Developer (Freelance)

Smile Open Source Solutions; Sint-Pieters-Woluwe; Hybride; EUR 73 800 - 129 150; Temps partiel

Résumé du poste

Smile Open Source Solutions in Brussels is seeking API/SOA Developers at Junior, Medior, and Senior levels to join our consultant pool. You will build, secure, and maintain modern APIs and SOA integrations for a premier Brussels client, bridging legacy systems with cloud infrastructure.

Expect to work in a hybrid setup (2-3 days remote) on diverse backend/API projects, collaborating in an Agile/Scrum environment with Jira/Confluence, and focusing on secure, scalable software delivery.

Qualifications

• 1 year of backend/API development for Junior, 3 years for Medior, 10+ years for Senior.
• Proficient in Java for APIs and web services.
• Experience with OAuth2/JWT/SOAP security and API management tools.

Responsabilités

• Develop high-quality backend APIs and services using Java within SOA, REST, and event-driven architectures.
• Implement and configure integration points across enterprise platforms such as Axway, Apigee, or WSO2.
• Incorporate robust security standards (OAuth2, JWT, SOAP security) and secure code using tools like Snyk and PKI.
• Deploy and manage applications within Public Cloud environments, utilizing Git and automation-driven CI/CD pipelines.
• Conduct thorough automated testing of web services to ensure stability, resilience, and performance.
• Work within an Agile/Scrum framework, using Jira and Confluence for documentation and sprint activities.

Connaissances

Java

API development

OAuth2/JWT/SOAP

Event-Driven Architecture

Cloud concepts

Security practices

Git/CI-CD

Testing web services

Agile/Scrum

English/French/Dutch ability

Outils

Axway

Apigee

WSO2

Jira

Confluence

Snyk

PKI

Git

Description du poste

Location: Brussels, Belgium (Hybrid: 2-3 days remote per week)

Contract Type: Freelance (Prestation de services)

Levels & Experience Required: Junior (1 year exp.) | Medior (3 years exp.) | Senior (10 years exp.)

Language Requirements: Fluent in English (3/4) OR fluent in Dutch/French (3/4)

About Smile: Why Join Us?

• Peer-to-Peer Management: Our proximity management by peers fosters 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 robust knowledge-sharing tools.

• Vibrant Community: Your year will be animated by group and agency events: annual convention, participation in trade fairs, summer party, and plenty of formal & informal afterworks.

Role Overview

On behalf of our fast-growing division, we are looking for API/SOA Developers at different seniority levels (Junior, Medior, and Senior) to join our consultant pool in Brussels.

In this role, you will be key to developing, securing, and maintaining modern API and Service-Oriented Architectures (SOA). Working on behalf of our premier client in Brussels, you will build clean, secure integrations and play a central part in bridging legacy systems with modern cloud infrastructure.

Key Responsibilities

Depending on your level of seniority, your responsibilities will include:

• API & SOA Development: Developing high-quality backend APIs and services using Java within SOA, REST, and event-driven architectures.

• API Management & Integration: Implementing and configuring integration points across enterprise platforms such as Axway, Apigee, or WSO2.

• Security & Vulnerability Management: Incorporating robust security standards (OAuth2, JWT, SOAP security) and securing code using tools like Snyk and PKI (Public Key Infrastructure).

• Cloud & CI/CD Pipelines: Deploying and managing applications within Public Cloud environments, actively utilizing Git and automation-driven CI/CD pipelines.

• Testing & Quality Assurance: Conducting thorough automated testing of web services to ensure system stability, resilience, and high performance.

• Agile Collaboration: Working within an Agile/Scrum framework, using Jira and Confluence for documentation, tracking, and sprint activities.

Your Profile

• Experience:

  • Junior: ~1 year of experience in backend/API development.

  • Medior: ~3 years of solid experience in API & middleware development.

  • Senior: 10+ years of deep expertise in complex enterprise integration and software development.

• Core Technical Skills:

  • Proficient in Java development applied to APIs.

  • Strong knowledge of API/Web Service standards and protocols (OAuth2, JWT, SOAP).

  • Hands‑on experience with API Gateway / ESB platforms such as Axway, Apigee, or WSO2.

  • Familiarity with Event‑Driven Architecture and public cloud concepts.

  • Solid understanding of security tools and practices (Snyk, PKI).

  • Experience with Git, CI/CD workflows, and web services testing frameworks.

• Methodology: Comfortable working in Agile/Scrum squads with tools like Jira and Confluence.

• Languages: Working proficiency (minimum 3/4) in English OR French/Dutch.