Owning the learning-to-rank stack end to end, including training data, features, model development, offline evaluation, production serving, and regression analysis
Improving the LambdaMART reranker and determining when gradient boosted trees are the appropriate solution
Designing and maintaining the offline evaluation framework, including NDCG@K, Precision@K, negative sampling strategies, dataset construction, and analysis of the gap between offline metrics and production behavior
Designing hybrid retrieval systems combining BM25 and dense vector search
Owning the recall budget feeding the reranker
Building feature sets for structured candidate-to-job matching, including skills coverage, seniority alignment, location and mobility signals, recency, and evidence strength
Handling sparse and partially populated profiles as a core design requirement, including calibration and monotonic constraints where needed
Diagnosing ranking quality regressions in production and identifying whether the root cause is related to features, labels, indexes, or models
Ensuring ranking decisions are explainable enough to satisfy Annex III obligations and support recruiter-facing explanations
Defining technical direction for matching systems
Reviewing contributions from other engineers working on the matching stack
Mentoring engineers on ranking fundamentals
Transforming interview transcripts and extracted claims into ranking features and supervision signals
Designing LLM-as-judge and weak supervision approaches for pairwise labels while managing label noise and consistency
Working on constrained extraction and span grounding to ensure claims are traceable to candidate statements
Contributing to interview integrity signals and confidence representation downstream
Using LLMs as components within larger systems rather than as core ranking models
Hands-on Machine Learning experience for 5+ years, with a focus on search, ranking, recommender systems, or relevance systems
Eperience building and operating production-grade ranking and retrieval systems for 3+ years
Strong practical experience with Learning-to-Rank, including gradient-boosted tree models such as LightGBM or XGBoost
Ability to explain and apply pairwise and listwise ranking objectives, selecting the appropriate approach based on real-world trade-offs
Strong expertise in ranking evaluation, including the development and maintenance of offline evaluation pipelines
Strong experimental rigor, including designing meaningful baselines; running ablation studies; distinguishing genuine improvements from noise, particularly with small or noisy evaluation datasets; reading and reproducing relevant research papers
Practical experience working with sparse, incomplete, or noisy data, including appropriate feature-engineering techniques
Experience generating scalable training signals without relying on manual annotation
Strong Python and ML engineering skills, including hands-on experience with scikit-learn
Ability to communicate complex technical topics clearly to both technical and non-technical stakeholders, including recruiters and compliance teams
Ownership of the full ranking funnel, from retrieval and recall through reranking and evaluation, including diagnosing ranking regressions and their root causes
Ability to approach data quality as a modeling challenge and balance relevance, latency, inference cost, and model complexity
Experience delivering production ML solutions independently, without relying on large infrastructure teams
Background in search, ads ranking, recommender systems, or marketplace ranking
Experience designing ranking benchmarks or evaluation metrics
Applied research experience through relevant publications or industrial research that resulted in production solutions
Level of English – from Upper-Intermediate and above
HRTech experience
Recruitment technology experience
Job marketplace or talent-matching experience
Vespa, Elasticsearch, or OpenSearch expertise, including index design and query tuning
Production experience with vector search technologies such as Vespa, FAISS, Qdrant, and Pinecone
Experience with model ensembling, including stacking and blending
Experience building regulated or auditable ML systems
LLMOps and experiment tracking experience
Experience with LangFuse
Experience in teamwork with leaders in FinTech, Healthcare, Retail, Telecom, and others. Andersen cooperates with such businesses as Samsung, Siemens, Johnson & Johnson, BNP Paribas, Ryanair, Mercedes, TUI, Verivox, Allianz, T-Systems, etc
The opportunity to change the project and/or develop expertise in an interesting business domain
Job conditions – you can work both fully remotely and from the office or can choose a hybrid variant
Guarantee of professional, financial, and career growth! The company has introduced systems of mentoring and adaptation for each new employee
The opportunity to earn up to an additional 1,000 EUR per month, depending on the level of expertise, which will be included in the annual bonus, by participating in the company's activities
Access to the corporate training portal, where the entire knowledge base of the company is collected and which is constantly updated
Bright corporate life (parties / pizza days / PlayStation / fruits / coffee / snacks / movies)
Certification compensation (AWS, PMP, etc)
Referral program
Private health insurance and sports compensation, depending on the type of employment