Software Engineer Backend (m/w/d)

Support Engineer (m/w/d) (English Speaker)

Location: Belvaux

Employment type: Permanent position, 40 hours/week, CDI (permanent contract)

Starting date: As soon as possible

Home-Office Option: Flexibel

Flexible working hours: yes, with core working hours 9:00 -18:00

About our client

Our clients is an innovative,

internationally oriented software company based in Luxembourg.

The company develops specialized

cybersecurity solutions and is an established provider of secure password and

digital credential management and sharing. Its solutions are used by companies

and organizations worldwide, helping them securely manage sensitive credentials

and efficiently organize access within teams.

The company combines open-source

technology with professional solutions for both cloud and on-premises

environments.

Your responsibilities

You will join the Backend Team and contribute to the development and continuous improvement of a growing portfolio of products, including self-hosted Community and Enterprise Editions as well as a managed Cloud Edition.

Your role will combine backend development, testing, technical analysis, documentation, deployment support, and close collaboration with Product, SRE, Security, Support, and other engineering teams.

As a Software Engineer, you will work on a security-first API responsible for data integrity, access rights management, secure integrations, and a seamless experience that can scale to organizations of all sizes.

Your

responsibilities will include:

• Developing new features in PHP and CakePHP for products used daily by more than half a million users
• Maintaining, improving, and fixing bugs in the existing codebase
• Transforming functional specifications into reliable API workflows while ensuring backward compatibility and security
• Designing and implementing robust business logic, REST API endpoints, and secure integrations
• Participating in code reviews to identify defects and potential improvements before release
• Writing unit tests with a target of 80% coverage to ensure functionality and prevent regressions
• Developing end-to-end tests covering critical user journeys and different usage scenarios
• Optimizing code for performance, scalability, maintainability, and simplicity
• Ensuring compatibility across multiple platforms and environments
• Supporting the Support Team in refining feature requests and bug reports received from customers and the community
• Collaborating with Product Owners to define effective functional approaches to new business cases
• Defining comprehensive and iterative technical approaches to complex functional problems
• Identifying opportunities for long-term structural and architectural improvements and proposing solutions
• Contributing to technical documentation, including OpenAPI specifications, SDKs, user guides, and administrator documentation
• Sharing technical findings, best practices, and knowledge internally through documentation and presentations
• Supporting release activities by preparing release readiness and assisting with rollout activities
• Collaborating closely with SRE teams to maintain reliable CI/CD pipelines and reduce deployment risks
• Providing technical support during incidents by investigating issues and implementing fixes to restore system stability
• Participating in blameless postmortems, contributing to root cause analysis, and implementing corrective actions in the codebase
• Managing your own priorities, deadlines, and deliverables to meet team commitments
• Communicating progress, risks, and technical decisions clearly and proactively
• Supporting colleagues through pair programming, knowledge sharing, and collaboration
• Ensuring that every change request includes an appropriate security risk analysis and proposed mitigations
• Applying secure coding and design practices throughout the development lifecycle
• Monitoring project dependencies for security vulnerabilities and supporting the Security Team in assessing their impact
• Patching dependency vulnerabilities while ensuring that updates do not introduce regressions
• Ensuring that product development activities comply with GDPR and other applicable data protection regulations
• Collaborating with Security and Senior Management to maintain up-to-date policies and risk registers
• Supporting the implementation of least-privilege access and appropriate segregation of roles and responsibilities
• Participating in security exercises and helping improve security, crisis management, and incident response processes

Your Profile

• Bachelor’s degree or university qualification in Software Engineering, Computer Science, Electronics, or a comparable field, or equivalent professional experience and certifications
• At least 3 years of professional experience developing PHP applications
• Strong experience building backend applications with CakePHP, Laravel, or Symfony
• Proficient in PHP and SQL
• Strong experience with PHPUnit and automated software testing
• Good knowledge of REST APIs and OpenAPI specifications
• Good knowledge of Git and modern branching models
• Experience with Docker and containerized development environments
• Good knowledge of Linux and macOS environments
• Experience with Bash or another programming language such as JavaScript, Python, Go, or Rust
• Strong understanding of OWASP Top 10 vulnerabilities and secure coding practices
• Familiarity with HTML, CSS, and Less
• Familiarity with Agile/Scrum development methodologies
• Experience working with Composer and modern PHP development workflows
• Knowledge of OpenPGP and GnuPG, or a strong interest in cryptography and secure software development
• Strong understanding of software quality, maintainability, performance, and scalability
• Strong analytical and problem-solving skills, with a preference for simple and effective solutions
• Ability to balance technical excellence with business priorities and strategic goals
• Comfortable working independently and taking ownership of your work while collaborating effectively with a team
• Receptive to feedback and committed to continuous improvement
• Fluent in written and spoken English; knowledge of another language is an advantage
• Genuine interest in cybersecurity, privacy, and building an ethical web
• Understanding of and enthusiasm for open source software and communities
• Comfortable working in a highly connected, internet-driven environment

Considered a plus:

• Experience developing large-scale, high-availability software systems
• Experience with end-to-end or performance testing
• Familiarity with evolutionary database design
• Experience with authentication technologies such as OAuth, JWT, WebAuthn, Duo, or Yubico
• Experience integrating user directories and identity systems such as LDAP, Active Directory, or SCIM
• Familiarity with UML and a willingness to use it for technical documentation
• Experience maintaining long-lived software projects
• Experience contributing to open source projects
• Experience working with remote teams in asynchronous environments
• Experience writing technical blog posts, articles, or giving technical talks
• Experience with cryptographic systems, OpenPGP, or GnuPG

Even if you do not meet every single requirement, we would still love to hear from you if you have a strong software engineering foundation, demonstrate a genuine interest in cybersecurity and privacy, and are motivated to learn and contribute to an open source product used by a large international community.

What you can expect

• A key role within the Backend Team, contributing directly to the development of core products
• The opportunity to work on a security-first application used daily by more than half a million users
• A wide variety of technical challenges involving PHP, CakePHP, APIs, cryptography, databases, testing, and distributed environments
• The opportunity to work across the complete software development lifecycle, from technical analysis and implementation through testing, deployment, and incident resolution
• Close collaboration with Product, Engineering, SRE, Security, Support, and other specialist teams
• The opportunity to contribute to architectural decisions and long-term improvements to the codebase
• The opportunity to work on a mature, long-lived open source project
• A strong focus on software quality, security, privacy, simplicity, and maintainability
• The opportunity to contribute to extensive technical documentation and share knowledge with colleagues and the wider community
• An environment where autonomy, ownership, feedback, and continuous learning are highly valued
• The opportunity to contribute to products and features requested by a large and active international community