AI/ML Engineer

Location: Remote, onsite, or hybrid from one of the listed countries: Albania, Austria, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Hungary, Italy, Kazakhstan, Kosovo, Kyrgyzstan, Latvia, Lithuania, Luxembourg, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Tajikistan, The Netherlands, Turkmenistan, Ukraine, or Uzbekistan.

Salary: EUR 3,050–5,000 per month gross. Additional earnings of up to EUR 1,000 per month may be included in the annual bonus.

Company

hirify.global delivers digital solutions and technology-driven services for businesses across multiple industries.

What you will do

• Own the learning-to-rank stack, including training data, feature engineering, model development, offline evaluation, production serving, and regression analysis.
• Improve LambdaMART reranking and design hybrid retrieval systems combining BM25 with dense vector search.
• Build structured candidate-to-job matching features covering skills, seniority, location and mobility, recency, and evidence strength.
• Design evaluation frameworks using NDCG@K, Precision@K, negative sampling, dataset construction, and offline-to-production analysis.
• Develop LLM-as-judge and weak supervision approaches for pairwise labels, constrained extraction, span grounding, and interview integrity signals.
• Define technical direction, review matching-stack contributions, and mentor engineers on ranking fundamentals.

Requirements

• 5+ years of hands-on machine learning experience focused on search, ranking, recommender systems, or relevance systems.
• 3+ years of experience building and operating production-grade ranking and retrieval systems.
• Strong Learning-to-Rank experience with gradient-boosted tree models such as LightGBM or XGBoost, including pairwise and listwise objectives.
• Strong Python and ML engineering skills, including scikit-learn, feature engineering, evaluation pipelines, and production ML delivery.
• Experience with sparse, incomplete, or noisy data; scalable training signals; ranking benchmarks; and diagnosing root causes of ranking regressions.
• Upper-Intermediate English or higher required.

Nice to have

• HRTech, recruitment technology, job marketplace, or talent-matching experience.
• Vespa, Elasticsearch, OpenSearch, FAISS, Qdrant, or Pinecone experience.
• Experience with model ensembling, regulated or auditable ML systems, LLMOps, experiment tracking, or LangFuse.

Culture & Benefits

• Fully remote, office-based, or hybrid work options.
• Mentoring and onboarding programs with opportunities for professional, financial, and career growth.
• Access to a corporate training portal and compensation for certifications such as AWS and PMP.
• Private health insurance and sports compensation, depending on the employment type.
• Referral program and corporate social activities.