Senior / Principal Software Engineer - SaaS Architecture & AI

Senior / Principal Software Engineer – SaaS / DelphiMaarssen (Utrecht) | 32–40 hours | Hybrid | Up to approx. €7,000 gross per month Still want to build and not just manage?For a fast-growing Dutch software company in transport and logistics, we’re looking for a Senior / Principal Software Engineer who still wants to stay genuinely hands-on. This is not the classic path where becoming senior means spending most of your time in meetings, people management and coordination. In this role, roughly 80% of your time is spent building software. The other 20% is focused on architecture, technical decision-making, problem solving, mentoring and challenging the team to build better software. You’ll work on a large, business-critical SaaS platform used by hundreds of logistics companies to manage processes such as order management, transport planning, Track & Trace, driver workflows, financial integrations and reporting. The platform is complex. And that’s exactly the point. This is not a legacy maintenance roleA large part of the codebase is written in Delphi, but don’t let that define the role. The company actively invests in the product, continuously refactors the codebase and applies modern software engineering principles to make the platform faster, more scalable and future-proof. That means working with topics such as: SOLID principlesDesign patternsSoftware architectureAutomated testingAsynchronous programmingPerformance optimisation and profilingDomain Driven DesignCI/CD and SaaS thinkingAI-assisted software developmentThe team has even built its own solutions and patterns where Delphi did not provide what was needed out of the box. So yes, strong Delphi experience is interesting. But we are deliberately looking broader. If you come from C#, .NET, Java, C++ or another serious engineering environment and you think in concepts rather than languages, we’d still like to talk. What will you work on?You’ll work end-to-end on a complex software product that sits at the heart of logistics operations. That means you won’t spend years maintaining one API or one isolated component. You’ll be involved in: designing, building and refactoring business-critical software;improving performance, scalability and maintainability;making and challenging architectural decisions;solving complex technical problems and production issues;improving automated testing and software quality;thinking about asynchronous and concurrent processing;working closely with Product, QA and other engineers;sharing knowledge and helping other developers grow;actively using AI and modern development tooling to improve your own workflow.You’re expected to have an opinion. Not because being opinionated is a goal in itself, but because seniority here means understanding the trade-offs, explaining them clearly and taking responsibility for the outcome. Who are we looking for?We’re looking for someone with real engineering depth. Ideally, you have: extensive experience as a Senior, Lead or Principal Software Engineer;strong object-oriented software engineering fundamentals;solid knowledge of SOLID principles and design patterns;experience with software architecture;experience with automated testing;experience in SaaS, product or CI/CD-driven environments;strong analytical and problem-solving skills;experience with performance analysis or profiling;a language-agnostic mindset;genuine curiosity about AI and emerging technology;strong enough English to work comfortably in an international development environment. Dutch is a plus, but not required. More importantly, we’re looking for someone who sees software engineering as a craft, not just a job. Someone who still wants to learn. Someone who asks why. Someone who doesn’t say: “That’s not my component.”But instead: “Why is this happening, and how do we solve it properly?” Seniority without leaving engineering behindJob titles are not that important to us. You may currently be called: Senior Software EngineerLead DeveloperPrincipal EngineerSoftware ArchitectWhat matters is that you can independently analyse complex technical problems, influence technical direction and still enjoy building software yourself. This is explicitly not a pure management position. The environmentThe internal development team consists of around ten engineers and works closely with Product, the CTO/architect, QA and external development teams. The company is moving quickly from a traditional software environment towards a SaaS-first model and continues to invest heavily in both technology and product development. AI is not treated as a future topic here. The expectation is that strong engineers are already experimenting with it, improving their workflow and thinking critically about what it means for software development over the next few years. The culture is direct, entrepreneurial and pragmatic. People challenge each other. You get freedom, but that freedom comes with ownership. If you need every task to be fully defined before you start, this probably won’t be the right environment. If you prefer: “Give me the problem, the context and the desired outcome — I’ll figure out the rest.” then it probably will. What’s in it for you?Depending on experience and level, the salary goes up to approximately €7,000 gross per month for an exceptional senior/principal profile. On top of that: 7% employer pension contribution;laptop budget of up to €4,500 for engineers;training and development budget;€400 comfort budget;home-office budget and remote-work allowance;company phone;20 holiday days, with the option to buy 5 additional days;hybrid working;sabbatical possibilities;strong focus on personal and professional growth. Because technical collaboration, knowledge sharing and whiteboard sessions matter, regular presence at the office in Maarssen is expected. The software is business-critical and used 24/7, so an occasional on-call rotation is part of the role. Why this role?Because you won’t be hired to simply keep an old system alive. You’ll join a company with a complex product, hundreds of customers, a strong growth ambition and a codebase they plan to keep investing in for years. And because the team is relatively small, your technical opinion will genuinely matter. If you’re a senior engineer who still sees software development as a craft and wants to stay technically sharp, we’d like to hear from you.