{"id":1892871,"url":"https://alion.io/job/zalo-leadsenior-data-scientist-adtima","title":"Lead/Senior Data Scientist, Adtima","company":{"id":183385,"name":"Zalo","domain":"zalo.me","url":"https://alion.io/company/zalo-2","size_band":null,"is_staffing_agency":false,"employer_type":"direct","is_intermediary":false,"listed_via":null,"ats_vendor":"Career site","truth_index":{"grade":"B","score":80,"open_postings":24,"ghost_share":0,"stale_share":0.583,"repost_share":0,"time_to_fill_p50_days":84,"computed_at":"2026-11-14T05:58:10Z"}},"role":"Data Science","role_family":"Data Science","seniority":"lead","employment_type":null,"work_mode":"on_site","remote_scope":null,"remote_scope_basis":null,"remote_working_hours":null,"hiring_geo_confidence":"structured","locations":["Ho Chi Minh City, Vietnam"],"countries":["VN"],"hiring_countries":[],"hiring_countries_total":0,"salary":null,"salary_estimate":{"min_usd":18500,"max_usd":43000,"period":"year","method":"global_role_cell_scaled_by_country","sample_n":771},"experience_years_min":5,"visa_sponsorship":false,"relocation_package":false,"has_equity":false,"technologies":[{"name":"A/B Testing","optional":false},{"name":"Embeddings","optional":false},{"name":"Knowledge Distillation","optional":false},{"name":"Model Distillation","optional":false},{"name":"Python","optional":false},{"name":"PyTorch","optional":false},{"name":"Recommender Systems","optional":false},{"name":"Spark","optional":false},{"name":"SQL","optional":false},{"name":"bandit","optional":true},{"name":"ClickHouse","optional":true},{"name":"Google BigQuery","optional":true},{"name":"LLM","optional":true}],"status":"live","first_seen_at":"2026-08-03T00:00:00Z","employer_posted_date":"2026-10-05","last_verified_at":"2026-11-14T22:47:23Z","board_verified":true,"closed_at":null,"days_open":104,"trust":{"level":"ok","repost_count":null,"flags":[],"days_open":104},"description":"We're hiring a Lead Data Scientist/Lead ML Engineer to own and improve Adtima's ads recommendation system - matching the most relevant ads from over 100,000 to 80 million Zalo users daily. Your models directly influence ad revenue and advertiser ROI.\nThe system covers retrieval, ranking, continuous retraining, and real-time serving (in collaboration with Backend / ML Ops). Your job is to understand, maintain, and develop it further. We welcome DS, ML Engineer, or Applied ML Research backgrounds.\nWhat you will do\nModel Development & Improvement\nIterate on ML models across the full pipeline - retrieval, ranking, engagement and conversion prediction. Explore new architectures (transformers, deep interaction networks, knowledge distillation), design better features, and tackle challenges like multi-task prediction, calibration, and cold-start for new campaigns;\nEnsure data quality across the ML lifecycle - validate labels, detect pipeline anomalies, understand sampling biases, and maintain data integrity.\nProduction Observability\nBuild observability that helps the team understand model behavior - prediction distribution, segment-level performance, and performance changes over time;\nMonitor data drift, training-serving skew, and prediction quality. Close the feedback loop between model predictions and real business outcomes;\nConduct exploratory data analysis on training data, features, and model outputs to uncover patterns, anomalies, and improvement opportunities.\nExperimentation\nLeverage the existing A/B testing infrastructure to evaluate model changes - design experiments, analyze results, and make informed deployment decisions;\nTechnical Direction\nDefine what to explore next, what data signals to acquire, and what improvements have the highest impact. Stay current with relevant advances in recommendation systems and deep learning;\nCollaborate with: Backend / ML Ops (deployment & serving), Data Engineering (pipelines & data availability), Product (business objectives & success metrics), Leadership (model performance visibility & technical direction).\nWhat you need\nLevel: Lead (5+ years of relevant experience)\nMust-have:\nDeep learning fundamentals + PyTorch (or equivalent). Experience with architectures used in recommendation/ranking (deep interaction networks, two-tower, attention/transformer-based);\nHands-on experience building recommendation or ranking models in production. Understanding of retrieval → ranking design;\nFeature engineering - embeddings, historical aggregation, cross-feature interactions;\nA/B testing for ML models - experiment design, statistical rigor, online/offline metric alignment;\nExperience building ML observability and monitoring in production;\nPython, SQL, data processing at scale (Spark). ML pipeline orchestration (Airflow or equivalent);\nClear communication - able to explain model behavior and trade-offs to engineering, product, and business stakeholders.\nNice-to-have:\nExperience in ad tech, e-commerce, marketplace, or any large-scale item selection/ranking domain;\nAuction/bidding mechanisms, prediction calibration, delivery optimization, or explore/exploit strategies (bandit algorithms, cold start);\nModel serving optimization, embedding-based retrieval, or vector databases;\nColumnar/OLAP databases (ClickHouse, BigQuery). AI/LLM tools for productivity.\nWorking style:\nHigh ownership - drives improvements end-to-end;\nExperiment-driven - benchmarks before committing, iterates based on evidence;\nHands-on - reads code, debugs pipelines, digs into data.","description_format":"text","description_chars":3535,"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":[],"hiring_locations":[],"hiring_excludes":[],"relocation_offered":false,"industries":[],"lifecycle":[{"event":"open","at":"2026-10-05T06:12:37Z"}],"visa":[],"liveness":{"score":23,"band":"cold","label":"Long shot","p_open":1,"p_active":0.529,"p_room":0.44,"age_days":103,"expected_fill_days":84,"reasons":["conf:2","stale_co","velocity","win:tail","crowd:"],"computed_at":"2026-11-14T05:58:10Z"},"pay":null,"html_url":"https://alion.io/job/zalo-leadsenior-data-scientist-adtima","json_url":"https://alion.io/job/zalo-leadsenior-data-scientist-adtima.json","meta":{"generated_at":"2026-11-15T03:42:41Z","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":7004,"day_limit":null,"remaining_today":null,"minute_limit":300,"resets_at":"2026-11-16T00:00:00Z"}},"offers":[{"id":"company.slices","title":"One company in depth, by slice","status":"live","price":{"credits":0.1,"usd":0.01,"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":183385},"rest":"https://alion.io/mcp/rest/get_company?id=183385"},"human":"https://alion.io/catalog?offer=company.slices&for=job%2Fzalo-leadsenior-data-scientist-adtima"},{"id":"market.stats","title":"A market slice: pay, demand and time to fill","status":"free","price":{"credits":0,"usd":0},"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%2Fzalo-leadsenior-data-scientist-adtima"},{"id":"job.search","title":"Open jobs by role, technology, place, pay and visa","status":"live","price":{"credits":0.1,"usd":0.01},"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%2Fzalo-leadsenior-data-scientist-adtima"},{"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/zalo-leadsenior-data-scientist-adtima\", \"note\": \"what you need it for\"}"},"human":"https://alion.io/catalog?offer=company.verify&for=job%2Fzalo-leadsenior-data-scientist-adtima"}],"agent":{"mcp":"https://alion.io/mcp/jobs","mcp_open":"https://alion.io/mcp/open","next":[{"tool":"get_job","arguments":{"id":1892871}},{"tool":"search_jobs","arguments":{"company":"zalo.me","detail":"compact"}},{"tool":"match_people","arguments":{"job_id":1892871},"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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