{"id":3272682,"url":"https://alion.io/job/kleinanzeigen-com-staff-backend-engineer-dfm","title":"Staff Backend Engineer (d/f/m)","company":{"id":2949074,"name":"Kleinanzeigen","domain":"kleinanzeigen.com","url":"https://alion.io/company/kleinanzeigen-com","size_band":null,"is_staffing_agency":false,"employer_type":"direct","is_intermediary":true,"listed_via":null,"ats_vendor":"HiBob","truth_index":null},"role":"Backend","role_family":"Backend","seniority":"staff","employment_type":null,"work_mode":"hybrid","remote_scope":null,"remote_scope_basis":null,"remote_working_hours":null,"hiring_geo_confidence":"structured","locations":["Berlin, Germany"],"countries":["DE"],"hiring_countries":[],"hiring_countries_total":0,"salary":null,"salary_estimate":{"min_usd":99000,"max_usd":182000,"period":"year","method":"role_seniority_country_remote_cell","sample_n":14},"experience_years_min":5,"visa_sponsorship":false,"relocation_package":false,"has_equity":false,"technologies":[{"name":"A/B Testing","optional":false},{"name":"ElasticSearch","optional":false},{"name":"Fine-tuning","optional":false},{"name":"Java","optional":false},{"name":"Kotlin","optional":false},{"name":"NumPy","optional":false},{"name":"Pandas","optional":false},{"name":"Python","optional":false},{"name":"Scala","optional":false},{"name":"Semantic Search","optional":false},{"name":"Vespa","optional":false},{"name":"Amazon S3","optional":true},{"name":"AWS","optional":true},{"name":"AWS Lambda","optional":true},{"name":"DuckDB","optional":true},{"name":"DynamoDB","optional":true},{"name":"Kubernetes","optional":true},{"name":"LLM","optional":true},{"name":"Spark","optional":true},{"name":"Trino","optional":true}],"status":"live","first_seen_at":"2026-10-26T09:22:14Z","employer_posted_date":"2026-10-26","last_verified_at":"2026-10-29T18:40:17Z","board_verified":true,"closed_at":null,"days_open":3,"trust":{"level":"ok","repost_count":null,"flags":[],"days_open":3},"description":"At Kleinanzeigen, search is the beating heart of how millions of users discover listings every day. We're evolving our search platform - moving to Vespa, expanding semantic and vector search capabilities, and building ranking models grounded in real buyer and seller signals. We're looking for a Senior Search Engineer who bridges the gap between search infrastructure and data science: someone who can both architect a high-performance retrieval pipeline and run rigorous offline experiments to validate relevance improvements.You'll join our Core Experience engineering team and work closely with Product, UX, and fellow engineers to shape search quality for one of Europe's largest classifieds platforms.\nResponsibilities\n What you'll do\n- Design and implement search features end-to-end: from indexing pipeline changes and schema design to query rewriting, ranking, and autocomplete.\n- Lead data-driven technical initiatives - write RFCs grounded in query log and user behaviour analysis, then own delivery from design to production.\n- Champion semantic and vector search: design embedding-based retrieval components, integrate LLMs for query understanding or evaluation, and measure real impact via A/B experiments.\n- Build and maintain offline evaluation pipelines (relevance judgment, NDCG, MRR) to accelerate the feedback loop between experimentation and deployment.\n- Improve indexing reliability and throughput - reduce re-ingestion times, ensure consistency, and tighten SLAs.\n- Contribute to the Vespa migration: design index schemas, relevance profiles, and deploy ML ranking models within the platform.\n- Collaborate cross-functionally with Data Science, Product, and other engineering teams; represent the team at technical forums and occasionally at external conferences.\nRequirements\n What we're looking for\nMust-have:\n- 5+ years of hands-on experience in search engineering - production-scale deployments using Elasticsearch, Solr, Vespa, or similar.\n- Strong data science fundamentals: experimental design (A/B testing, interleaving), relevance evaluation, and statistical analysis with Python (Pandas, NumPy, Jupyter).\n- Solid software engineering skills in at least one JVM language (Kotlin, Java, or Scala) plus Python.\n- Deep familiarity with vector/semantic search: dense retrieval, approximate nearest neighbour (ANN), embedding fine-tuning or prompting for query/document understanding.\n- Track record of authoring and leading technical proposals based on data analysis - not just implementing specs written by others.\nNice-to-have:\n- Experience with Vespa or migrating from Solr/Elasticsearch to Vespa.\n- Familiarity with LLM-based approaches to data labelling, evaluation set generation, or query augmentation.\n- Experience with big data tooling (Spark, Trino, DuckDB) for large-scale offline analysis.\n- AWS cloud experience (S3, DynamoDB, Lambda, Kubernetes).\n- Conference talks, published work, or open-source contributions in the search/IR space.\nBenefits\nAt Kleinanzeigen, we care about our people - their wellbeing, growth, and life beyond work. Our benefits are designed to support you holistically, giving you flexibility and opportunities to thrive.Flexibility\n28 business days of paid annual holidays\n20 days “work from anywhere”\nFlexible working time (hybrid)\nPaid additional parental leave for both parents\nExtra paid days off for special occasions (e.g. your wedding or a move)\n Wellbeing & SupportPrivate health insurance\nGym Pass (may cover up to 70% of gym membership fees) \n40€ per month as a remote working allowance. \n Growth & DevelopmentPersonal development budget\nLearning opportunities to grow your skills and career\nA unique position in an international and dynamic environment\nA flat, collaborative culture where your feedback actively shapes our processes\n Perks & Everyday BenefitsCompetitive compensation package (Base salary + annual bonus)\nFlexible Remuneration Program (tax-efficient options for transport, restaurant vouchers and childcare)\nCorporate benefits and exclusive discounts\nAn attractive referral program\nKleinanzeigen is an equal opportunity employer that values diversity and inclusion. We welcome people of all backgrounds, races, religions, colours, national origins, gender identities, sexual orientation, ages, marital status, or disability status.If this role sparks your interest but you’re not sure you meet every single requirement, we’d still love to hear from you anyway!","description_format":"text","description_chars":4453,"description_truncated":false,"requirements":{"experience_years_min":5,"management_years_min":null,"team_size_min":null,"manages_managers":false,"education":null,"security_clearance":false,"languages":[]},"benefits":["Flexible schedule","Gym membership","Health insurance","Parental leave"],"hiring_locations":[{"name":"Germany","iso":"DE","kind":"country"}],"hiring_excludes":[],"relocation_offered":false,"industries":["Internet Services","Marketplaces","Online Classifieds"],"lifecycle":[{"event":"open","at":"2026-10-26T12:32:14Z"}],"visa":[],"liveness":{"score":90,"band":"hot","label":"Hiring now","p_open":1,"p_active":0.903,"p_room":1,"age_days":2,"expected_fill_days":48,"reasons":["conf:0","velocity","win:early"],"computed_at":"2026-10-29T05:49:05Z"},"pay":null,"html_url":"https://alion.io/job/kleinanzeigen-com-staff-backend-engineer-dfm","json_url":"https://alion.io/job/kleinanzeigen-com-staff-backend-engineer-dfm.json","meta":{"generated_at":"2026-10-29T19:08:25Z","cache_seconds":300,"methodology":"https://alion.io/methodology","terms":"https://alion.io/terms","contact":"https://alion.io/contact","api":"https://alion.io/developers","about":"Alion is a live layer of people, companies and AI agents: who they are, whether they are real and active right now, what they do and how to work with them, readable by people and by agents and paid per call.","catalog":"https://alion.io/catalog.json","usage":{"tier":"crawler_verified","counted_by":"address","units_charged":1,"used_today":28453,"day_limit":null,"remaining_today":null,"minute_limit":300,"resets_at":"2026-10-30T00:00:00Z"}},"offers":[{"id":"company.slices","title":"One company in depth, by slice","status":"live","price":{"credits":0.02,"usd":0.002,"plus_per_slice":{"credits":0.05,"usd":0.005}},"unit":"per company, plus each slice with data","note":"the employer in depth","call":{"mcp_tool":"get_company","arguments":{"id":2949074},"rest":"https://alion.io/mcp/rest/get_company?id=2949074"},"human":"https://alion.io/catalog?offer=company.slices&for=job%2Fkleinanzeigen-com-staff-backend-engineer-dfm"},{"id":"market.stats","title":"A market slice: pay, demand and time to fill","status":"live","price":{"credits":1,"usd":0.1},"unit":"per slice","note":"pay, demand and time to fill for this role and place","call":{"mcp_tool":"market_stats"},"human":"https://alion.io/catalog?offer=market.stats&for=job%2Fkleinanzeigen-com-staff-backend-engineer-dfm"},{"id":"job.search","title":"Open jobs by role, technology, place, pay and visa","status":"live","price":{"credits":0.02,"usd":0.002},"unit":"per posting in a list","note":"similar open postings","call":{"mcp_tool":"search_jobs"},"human":"https://alion.io/catalog?offer=job.search&for=job%2Fkleinanzeigen-com-staff-backend-engineer-dfm"},{"id":"company.verify","title":"Is this company real and active right now","status":"pilot","price":null,"unit":"per company","request":{"url":"https://alion.io/catalog/request","method":"POST","body":"{\"offer\": \"company.verify\", \"for\": \"job/kleinanzeigen-com-staff-backend-engineer-dfm\", \"note\": \"what you need it for\"}"},"human":"https://alion.io/catalog?offer=company.verify&for=job%2Fkleinanzeigen-com-staff-backend-engineer-dfm"}],"agent":{"mcp":"https://alion.io/mcp/jobs","mcp_open":"https://alion.io/mcp/open","next":[{"tool":"get_job","arguments":{"id":3272682}},{"tool":"search_jobs","arguments":{"company":"kleinanzeigen.com","detail":"compact"}},{"tool":"match_people","arguments":{"job_id":3272682},"note":"people open to offers who fit this vacancy"}],"note":"The same data through MCP tools: https://alion.io/mcp/open needs no sign-in (compact searches, postings, people); https://alion.io/mcp with an Alion account has everything. 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