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Keystone Solutions

IT Developer - Senior

Keystone Solutions
Belgium · Full-time · Not Applicable
Mission Overview:

This is a consultancy mission through Keystone Solutions to support our clients Agile transformation within their enterprise digital channels. As a Keystone Solutions consultant, you will work closely with the clients multi-disciplinary squads that own end-to-end products for enterprise customers, developing and maintaining web and mobile solutions backed by cloud-based services. You will contribute to features across the stack (including backend services and integrations) while collaborating in an Agile, DevOps-oriented environment.

Assignment Details:

  • Role: Back-end Developer (Java)
  • Model: Keystone Solutions consultancy mission, working on-site with the client
  • Location: Brussels, Belgium (on-site at the client)
  • Team: You will join an Agile squad composed of internal and external members, with responsibilities spanning both development and operations.


Key Responsibilities:

  • Translate requirements into high-quality code as a Keystone Solutions consultant embedded with the client.
  • Design, build, and maintain high-performance, reusable, and reliable applications.
    • Backend focus: Java and Spring Framework (this will be most of your activities).
  • Collaborate with cross-functional teams to ship new features.
  • Work with outside data sources and APIs.
  • Ensure the best possible performance, quality, and responsiveness of the application.
  • Apply development best practices to ensure the quality of your code.
  • Identify and correct bottlenecks and fix bugs.
  • Be involved in Ops activities, including the setup of CI/CD pipelines.
  • Contribute to features end-to-end across the clients digital ecosystem (web, mobile, cloud backend).

Language and Education Requirements:

  • English: Sound knowledge of English is required. Knowledge of French or Dutch is a plus.
  • Education: Bachelor/Master or equivalent by experience.


Agile Mindset:

  • A positive attitude and pragmatism.
  • Thirst for knowledge: Agile is about learning and adapting. Knowledge sharing is key to success.
  • The goal of team success: Agile is about the success of the team, not individual heroics. It is more important for the team to succeed than for an individual to complete their own tasks.
  • There is no failure, only feedback: take everything as lessons, adjust actions based on feedback, and continuously improve.


Beyond roles: Agile teams are cross-functional. All required disciplines are represented in the team (analysis, development, testing, etc.). Although team members have a primary role, they are expected to take on other roles and contribute to other disciplines whenever it helps reach the sprint goal.

Required Experience and Knowledge:

  • At least 6 years of relevant experience.
  • You are a Software Craftsman who sees software development as a craft.
  • You know the principles of clean code and apply them effectively.
    • Understanding of OO principles, DDD, design patterns, and best practices such as SOLID principles.
    • You write readable code and perform refactoring where necessary.
    • You are familiar with Test Driven Development (TDD) and have practical experience with it.
    • Willing to pair.


Technical Skills (Mandatory):

  • Proven knowledge of Java, Spring, Maven, and databases.
  • Proven knowledge of RESTful APIs with Swagger (YAML).
  • Proven knowledge of version control systems (Git).
  • Proven knowledge of Continuous Integration/Deployment principles (Jenkins or alternative).
  • Proven knowledge of SAST (such as SonarQube, Fortify, NexusIQ or alternatives).
  • Knowledge of Docker, containers, and Groovy.
  • Participation in API automation testing as part of your development activities.


Nice to Have:

  • React
  • Node.js
  • Business experience: preferable
  • Specific requirement for Agile: practical experience with Scrum


Soft Skills:

  • Actively share knowledge with other developers (practices, technical topics) and suggest improvements to squad members; constantly seek to improve the squads way of working.
  • Easily adapt and bond with new colleagues.
  • Collaboration and feedback are key elements of your personality.
  • Dare to challenge requirements based on your expertise.


Consultancy Nature of Work with Keystone Solutions:

  • You will be a Keystone Solutions consultant, operating on-site with the client within their Agile squads.
  • You will collaborate closely with client stakeholders while being supported by Keystone Solutions expert community, methodologies, and delivery standards.
  • Your work will follow the clients context and priorities, with Keystone Solutions ensuring quality, craftsmanship, and continuous improvement in every engagement.


Dynamic Projects Across Clients:

  • Engage with complex, real-world challenges in enterprise-grade environments.
  • Build resilient backend services and integrations that power high-usage digital channels.
  • Following this mission, you will have opportunities to contribute to other strategic client projects through Keystone Solutions, broadening your impact and experience.


Turbo-Charged Learning and Development:

  • Access to peer coaching, knowledge-sharing sessions, and expert communities at Keystone Solutions.
  • Support for certifications and mastery of modern engineering practices (Clean Code, TDD, CI/CD, Cloud, Security).
  • Personalized growth plans aligned with your technical ambitions and consulting path.


Ambition Skyrocketing within a Consultancy Framework:

  • Accelerate your career by delivering measurable impact across varied client contexts.
  • Take on increasing scope: from feature ownership to architecture contributions and DevOps improvements.
  • Develop as a trusted advisor while staying hands-on with code and delivery excellence.


Keystone Solutions Values in Action:

  • Craftsmanship: we build clean, maintainable, and secure software.
  • Ownership: we take responsibility end-to-end, from design to operations.
  • Client Impact: we focus on outcomes that matter for users and the business.
  • Team Spirit: we succeed together through feedback, pairing, and knowledge sharing.
  • Curiosity and Integrity: we learn continuously and act with transparency.


Being a K‑Stone means bringing these values to each client project, every day.

Role-Specific Consulting Opportunity:

  • As a Senior Java Backend Developer, you will apply your expertise in Java, Spring, APIs, CI/CD, and SAST to elevate the clients digital products while leveraging Keystone Solutions consulting toolkit.
  • You will strengthen Agile and DevOps practices within the squad, contribute to automation and quality gates, and mentor peers through pairing and code reviews.
  • Your E2E mindset and clean code approach will help the client deliver robust, scalable, and secure enterprise features.


If you are ready to tackle technical and strategic challenges in a dynamic consultancy environment, apply today at Keystone Solutions Career Portal.

Key Skills

Ranked by relevance

java devops cloud cicd tdd design patterns restful apis embedded jenkins docker maven ddd
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Country Guide

Belgium

International hub for EU careers

Posted
Jan 18, 2026
Type
Full-time
Level
Not Applicable
Location
Brussels
Company
Keystone Solutions

Industries

Information Technology & Services

Categories

Engineering Information Technology

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