Full Stack and Mobile Developer Technical Lead

Keystone Solutions; Brussel Hoofdstad; On-site; EUR 92,000 - 148,000; Full time

Job summary

Keystone Solutions is seeking a senior Full-Stack and Mobile Developer / Technical Lead for a consultancy mission at a client site. You will define architecture, lead development, and ensure quality across mobile and web platforms.

You bring 8+ years of experience, strong communication and leadership skills, and are comfortable working at a client site in Belgium. Fluency in English, French or Dutch is expected, with a focus on delivering robust, scalable software solutions.

Qualifications

• 8+ years of software development experience, with hands-on senior technical leadership.
• Strong architecture, design patterns and multi-tier systems knowledge.
• Experience in .NET stack, frontend JS frameworks, and mobile tech.

Responsibilities

• Define and maintain software architecture for scalable, secure solutions.
• Translate business needs into robust technical designs and choices.
• Lead development and review code to ensure quality and consistency.
• Mentor developers and promote knowledge sharing and best practices.
• Identify risks, dependencies and debt; propose effective mitigations.
• Contribute to testing, release, and deployment of mobile apps.

Skills

Technical leadership

Architectural design

Backend development

Frontend development

Mobile development

React Native

Nuxt.js

Vue.js

C# / .NET

REST API

Unit testing

OpenID Connect

IdentityServer

Docker

Kubernetes

Azure DevOps

Git

JQuery/JS

Tools

Azure DevOps

Git

Docker

Kubernetes

Expo

React Native

Nuxt

OpenID Connect

Identity Server

NUnit

xUnit

jQuery

VueJS

Job description

Mission Overview

Keystone Solutions is seeking a Full-Stack and Mobile Developer / Technical Lead for a consultancy mission at a client site. This role requires strong technical expertise and a minimum of 8 years of experience in software development. As a consultant, you will be representing Keystone Solutions while working on dynamic projects that offer diverse challenges.

Responsibilities

• Define and maintain the technical architecture of software solutions, ensuring scalability, security, performance, and maintainability.
• Translate business requirements into robust technical designs and appropriate technology choices.
• Actively contribute to software development, particularly for complex or critical components.
• Ensure code quality and architectural consistency through code reviews, technical standards, and best practices.
• Provide technical guidance and support to developers, stimulate knowledge sharing and continuous improvement.
• Identify technical risks, dependencies, technical debt, and drive appropriate solutions.
• Collaborate with the head of service and project managers to ensure successful project delivery.
• Actively participate as a member of project teams, contributing directly to the design, development, testing, and delivery of software solutions.
• Develop and maintain mobile applications.
• Contribute to the testing, release, and deployment of mobile applications on the Google Play Store and Apple App Store.

Required Technical Skills

• Object-oriented programming, design patterns, n-tiers architecture.
• Backend: C#, .NET Framework 4.0/4.5/4.8, .NET Core, .NET Core WebApi, Entity Framework.
• Front end: HTML, CSS, JavaScript, jQuery, SCSS/SASS, Nuxt.js, Node.js, VueJs.
• Database: MS SQL Server, TSQL.
• DevOps and containerization: MS Azure DevOps, Git, Docker, Kubernetes.
• Mobile development: React Native, Expo, deployment (Google Play, App Store).
• Unit testing: NUnit, xUnit.
• IdentityServer, OpenId Connect and web applications security.
• Rest API services.

Soft Skills and Personal Competencies

• Technical leadership: ability to guide and advise colleagues.
• Communication: ability to explain technical concepts and standards.
• Collaboration: strong teamwork and ability to work effectively with developers, project managers, and designers.
• Accountable: proactive approach in risks identification, take responsibilities.
• Continuous learning: willingness to learn new technologies, continuously improve technical skills.
• Knowledge sharing: ability to advise colleagues, share expertise.

Languages

• French or Dutch (read, written, spoken).
• English (read, written, spoken).

At Keystone Solutions, we are committed to turbo-charged learning and skyrocketing ambition.

Duration

23/11/2026 - 26/02/2027 4 months (full time)

Skills required

• Azure DevOps - Level: Confirmed - Most recent: Any time
• Azure DevOps (GIT) - Level: Confirmed - Most recent: Any time
• C# / .NET (Core, 10) - Level: Confirmed - Most recent: Any time
• C#: ASP.NET Core (REST API) - Level: Confirmed - Most recent: Any time
• C#: ASP.NET MVC - Level: Confirmed - Most recent: Any time
• Docker - Level: Confirmed - Most recent: Any time
• Expo - Level: Confirmed - Most recent: Any time
• identity Server - Level: Confirmed - Most recent: Any time
• jQuery/JS - Level: Confirmed - Most recent: Any time
• Kubernetes - Level: Confirmed - Most recent: Any time
• NUnit - Level: Confirmed - Most recent: Any time
• Nuxt - Level: Confirmed - Most recent: Any time
• OpenID-Connects - Level: Confirmed - Most recent: Any time
• React native - Level: Confirmed - Most recent: Any time
• VueJS - Level: Confirmed - Most recent: Any time
• xUnit - Level: Confirmed - Most recent: Any time

Language requirements

• French or Dutch (read, written, spoken).
• English (read, written, spoken).