Senior Software Engineer

Lefebvre Sdu; Den Haag; Hybrid; EUR 61,000 - 72,000; Full time

Benefits offered by this job

Salary 5,500–6,450 €/mo

4% year-end bonus

Profit sharing up to 6%

23 vacation days

12% personal choice budget

Pension plan

Travel allowance

Bike plan

Two days in The Hague office

Growth opportunities

Job summary

Lefebvre Sdu is building GenIA-L, an AI-first platform for legal and tax knowledge. We seek a Senior Software Engineer to own backend services, including authentication, authorization, and user management, with frontend collaboration as needed. The role centers on robust, scalable Node.js components and API design.

You’ll join a team in The Hague with a hybrid work model, 2 days in the office, and a focus on delivering a high-quality platform used by thousands of professionals across Europe.

Qualifications

• Proficient in TypeScript and Node.js with production experience.
• Strong knowledge of OAuth 2.0 / OIDC and authentication/authorization systems.
• Familiarity with React/Next.js and GraphQL/APollo.
• Experience with relational DBs (Postgres, SQLite, MariaDB) and Redis.

Responsibilities

• Own backend services around authentication and user management.
• Develop and maintain Node.js components, including PDF export and chat delivery via Redis.
• Collaborate with frontend, product owner, and stakeholders to improve stability and scalability.
• Document systems and drive continuous improvement, stabilization, and simplification.

Skills

TypeScript

Node.js

OAuth 2.0 / OIDC

GraphQL / Apollo

Postgres / SQLite / MariaDB

Redis

Docker

CI/CD

AWS / Kubernetes / Helm

Prisma / MikroORM

React / Next.js

Tools

Redis

Docker

GitHub Actions

AWS

Kubernetes

Helm

Prisma

MikroORM

React

Next.js

Job description

Job Description

Legal AI is only as good as the knowledge behind it. At Lefebvre Sdu, we've been building that knowledge for over 200 years. Day in, day out. Law by law. Word by word. As the Dutch heart of Lefebvre Group, the European leader in legal and tax knowledge, we're also developing our own platform: GenIA-L, where lawyers and tax advisors don't just get an answer, but an answer they're willing to attach their name to. More than 75,000 professionals use it daily, generating over 100 million euros in ARR across Europe. We're looking for a Senior Software Engineer to help build that.

How You'll Move Us Forward

We're bringing separate knowledge portals together into one platform, with AI as the primary way users interact with our platform. We're building GenIA-L: an agentic AI solution that understands and answers legal questions based on our own, trusted content. With you on board, the team will be able to take end-to-end ownership of its own components. In practice, the role is backend-first: you'll take ownership of business-critical Node.js services around authentication, authorization, and user management, along with components like PDF export and chat delivery via Redis. Ownership in this role at Lefebvre Sdu means actively driving continuous improvement, stabilization, and simplification of these systems: so you won't just be keeping the lights on. Frontend work will also come up, so a solid frontend level is desired. The product is under active development, so what you build and improve now will determine how stable and scalable this platform is a year from now.

Job Requirements

WHAT WE'RE LOOKING FOR

Technical depth is a non-negotiable. You have extensive experience with TypeScript and Node.js , preferably with authentication and authorization systems in production environments, as this is the most important part of the role. You're well-versed in OAuth 2.0 / OIDC flows and aren't afraid to untangle complex system integrations around permissions and roles. You take ownership: you're comfortable with stakeholder management and proactively drive improvement, simplification, stabilization, and documentation. Frontend doesn't need to be your greatest strength, but you should be good enough at it to pick it up from time to time.

• TypeScript / Node.js and related frameworks (e.g., NestJS, Koa)


• Authentication and authorization (OAuth 2.0 / OIDC)


• GraphQL / Apollo


• Relational databases (Postgres, SQLite, MariaDB) and Firebase


• Redis


• Docker, CI/CD (GitHub Actions)


• AWS / Kubernetes / Helm is a strong plus


• Familiarity with ORMs (e.g., Prisma, MikroORM)


• Familiarity with React / Next.js

What You're Signing Up For

At Lefebvre Sdu, you'll work in an organization that's in the middle of a transformation and takes the public market seriously. That's the direction, and we're making the journey together. You'll get the mandate, the space, and the colleagues to make it happen.

You'll join a team with a Product Owner, three frontend developers, a UX designer, and a Scrum Master who also works across multiple teams. You'll have room to shape your role and help determine how we work, with a clear shared goal: building the AI-first platform. You'll bring the backend experience the team needs to take real end-to-end ownership, and you'll report to the Lead Frontend Developer. You'll take part in the team's regular scrum rituals (dailies, refinements, retros, planning) and have one-on-ones with your manager. Through the team, you'll also be an important point of contact for application administrators and customer support who need technical assistance, so you should enjoy breaking down technical problems and communicating about them with less technical colleagues.

• A place where you have influence from day one: on the approach, the processes, and the direction.


• Colleagues who deliberately chose Lefebvre Sdu over big tech jobs because here, they're building something that doesn't exist yet.


• Salary between €5,500 and €6,450 per month, based on a 36-hour week, since that's full-time for us.


• A bonus tied to company performance: a fixed year-end bonus of 4% and profit sharing of up to 6%.


• 23 vacation days and a personal choice budget of 12%, of which 8% is holiday pay and 4% is freely allocable. Want more vacation? Just buy it.


• A solid pension plan through PGB, including supplementary partner insurance.


• Collective insurance plans.


• A travel allowance of €0.25 per kilometer or a public transport reimbursement, plus an attractive bike plan. For employees with a commute of less than 10 km or more than 60 km, we have an adjusted arrangement.


• Two days a week in the office in The Hague, within walking distance of Voorburg station. The rest of the week, wherever you work best.


• Room to grow: in your craft, in your role, in the organization.

A reference check and a VOG (certificate of good behaviour) are part of the selection process.