Senior Data Engineer

ppPeople used to search on Google. Now they ask ChatGPT, Gemini and Perplexity what to buy and which brand to trust, and soon AI will buy for them. /ppMentionLab shows businesses how AI sees them: what AI engines say about their brand, how they compare to competitors, and which sources shape those answers. We're building the data and intelligence layer for AI Search and agentic commerce. /ppBorn in Brussels and global from day one, we already serve leading brands directly and through major consultancies and agencies. /ppWe're moving fast in one of the biggest shifts in how people discover information, and we're looking for people who want to build incredible things with us. /ph3The Role /h3pAs a Senior Data Engineer at MentionLab, you'll own the data layer at the heart of our product. You'll design and run the pipelines that turn raw AI answers into reliable, structured data. You'll also build the ClickHouse models that power our analytics platform and partner deliveries. Our pipelines are built in Node.js and TypeScript, so this role suits a data engineer with strong software engineering skills. If you love analytical databases at scale, care deeply about data quality, and want to own meaningful parts of a product from day one, this role is for you. /ph3What You'll Build /h3ulliOwn our data architecture end to end: ingestion, transformation, storage and delivery /liliBuild and scale the pipelines that process what AI engines say across markets, languages and models /liliDesign ClickHouse data models and queries that stay fast as volumes grow /liliGuarantee data quality through validation, deduplication, monitoring and backfills /liliRun high-throughput, queue-based processing reliably in production /liliWork mainly in TypeScript and SQL, with Rust for performance-critical processing /liliRaise the engineering bar through code reviews, standards and mentoring /li /ulh3The Stack /h3ulliTypeScript (Node.js) and SQL, with some Rust; /liliNestJS with MikroORM and Knex on PostgreSQL; /liliClickHouse for analytical workloads; /liliRedis for queue management (BullMQ + custom tooling for high throughput). /li /ulh3What We're Looking For /h3pTechnical

Requirements:
/pulli5+ years of engineering experience, including building and running production data pipelines /liliStrong, hands-on experience with data modelling, query optimisation and performance tuning on an analytical database (ClickHouse strongly preferred) /liliSolid Node.js/TypeScript

skills:
our pipelines are written in TypeScript, not Python /liliAdvanced SQL /liliExperience with queue-based or event-driven processing at scale (retries, idempotency, backpressure) /liliComfortable working across both analytical and transactional databases /liliExperience with AI-assisted development tools (Copilot, Cursor, Claude Code, or similar) /li /ulpWhat We Value: /pulliProactive mindset: spot issues, propose solutions, don't wait to be told /liliComfortable with code reviews and constructive feedback /liliCare about data quality and code quality, but know when to ship fast /li /ulpNice to Have: /pulliRust experience, or strong interest in picking it up /liliExperience with NestJS, PostgreSQL, Redis/BullMQ /liliProcessing unstructured or multilingual text data (e.g. LLM outputs) /liliDelivering data to external consumers (APIs, exports, data feeds) /liliPrevious startup experience /li /ulh3You’ll Thrive Here If /h3pYou enjoy figuring things out and don't need hand-holding. You're comfortable with ambiguity and changing priorities. You like collaborating and sharing what you learn. You're excited about AI and its impact on how people discover information. And you're AI-native: you don't just build AI products, you build with AI. /ph3How We Work /h3pLanguages: French required. English working proficiency for documentation and some meetings.

Location:
Belgium-based (Brussels
- hybrid). Permanent contract (CDI)
- 38h/week. /ph3What

We Offer
/h3pFair salary package including car/mobility budget and insurance /ppSmall, ambitious team /ppA chance to shape the technical direction of the company /ppHigh level of autonomy with guidance when needed: you're not alone /ppYou’ll hear back from us fast, positive or negative. We won't ghost you. /ppImportant note: we hire people, not roles. If you're excited about this opportunity but don't check every box, we'd love to hear from you. This is a guide, not a checklist. /p /p