{"id":108125,"url":"https://alion.io/job/sonarsource-ai-researcher-post-training","title":"AI Researcher - Post-Training","company":{"id":4925,"name":"SonarSource","domain":"sonarsource.com","url":"https://alion.io/company/sonar","size_band":"1001-5000","is_staffing_agency":false,"employer_type":"direct","is_intermediary":false,"listed_via":null,"ats_vendor":"Lever","truth_index":{"grade":"A","score":91,"open_postings":89,"ghost_share":0,"stale_share":0.146,"repost_share":0,"time_to_fill_p50_days":81,"computed_at":"2026-10-22T06:10:10Z"}},"role":"AI/ML","role_family":"AI/ML","seniority":"middle","employment_type":"full_time","work_mode":"on_site","remote_scope":null,"remote_scope_basis":null,"remote_working_hours":null,"hiring_geo_confidence":"structured","locations":["London, United Kingdom"],"countries":["GB"],"hiring_countries":[],"hiring_countries_total":0,"salary":null,"salary_estimate":null,"experience_years_min":4,"visa_sponsorship":false,"relocation_package":false,"has_equity":false,"technologies":[{"name":"AI Agents","optional":false},{"name":"C#","optional":false},{"name":"C++","optional":false},{"name":"Java","optional":false},{"name":"LLM","optional":false},{"name":"Machine Learning","optional":false},{"name":"Post-training","optional":false},{"name":"Python","optional":false},{"name":"Rust","optional":false},{"name":"SonarQube","optional":false},{"name":"Fine-tuning","optional":true},{"name":"GRPO","optional":true},{"name":"PEFT","optional":true},{"name":"PPO","optional":true},{"name":"SFT","optional":true},{"name":"Synthetic Data","optional":true},{"name":"Transformers","optional":true}],"status":"live","first_seen_at":"2026-08-05T16:19:17Z","employer_posted_date":"2026-08-05","last_verified_at":"2026-10-22T09:23:09Z","board_verified":true,"closed_at":null,"days_open":77,"trust":{"level":"ok","repost_count":0,"flags":[],"days_open":77},"description":"Position description\nAt Sonar, we are seeking an ambitious senior researcher to join our cross-disciplinary team, innovating and developing the next generation of solutions to build enterprise-grade coding agents and models. You will harness Sonar’s deep experience in static analysis, and combine it with your experience and leading techniques in large language model post-training. If you are interested in being hands-on with state-of-the-art research, building practical solutions that deliver high-impact for customers, and working within a team of innovative researchers and engineers, this role is for you.\nWhat you will do\nOutcome Driven Development: Work in a team developing and implementing advanced products that enable customers to post-train models to power their agentic coding practices. These agents need to generate high-quality code that meets their enterprise standards and software development best practices.\n\nTranslate Prototypes to Products: Collaborate closely with researchers, research engineers, MLOps and engineers within the team to design hypotheses and experiments, iterate proofs-of-concept quickly and develop successful prototypes into cutting-edge products.\n\nSubject Matter Expert: You will contribute and discuss ideas within our cross-disciplinary team, driving towards the next generation of coding model post-training for enterprises.\n\nSpearhead Research & Innovation: Stay up-to-date with the latest LLM and agentic developments; you are driven by learning and teaching others. You will need to explain complex technical details and concepts to both technical and non-technical audiences.\n\nExperience and qualifications\nThe ideal candidate will have:\nAn advanced academic background (Master’s or PhD) in Computer Science, Machine Learning, or a related quantitative field.\n\n4+ years industry experience in machine learning, with a solid understanding of modern software engineering practices and tools.\n\nFluency with Python including core ML frameworks, experience with Rust or any of SonarQube’s flagship languages (C#, C++, JS/TS, Java) is a plus.\n\nExpertise in post-training of large language models, including:\n\nPolicy optimization algorithms (e.g. GRPO, PPO)\n\nVerifier-based RL frameworks (RLVR)\n\nSupervised fine-tuning (SFT)\n\nData-centric AI methods, including synthetic data and curation\n\nParameter-efficient fine-tuning (PEFT)\n\nPreference and Safety Alignment\n\nExperience of driving research projects, delivering valuable findings and prototypes, and then converting them into products.\n\nExcellent communication skills in English and a talent for explaining complex scientific topics clearly and concisely.","description_format":"text","description_chars":2655,"description_truncated":false,"requirements":{"experience_years_min":4,"management_years_min":null,"team_size_min":null,"manages_managers":false,"education":{"level":"master","optional":false},"security_clearance":false,"languages":[{"language":"English","level":"All levels","optional":true}]},"benefits":[],"hiring_locations":[],"hiring_excludes":[],"relocation_offered":false,"industries":["Application Security","Software Testing & QA","Developer Tools"],"lifecycle":[{"event":"open","at":"2026-08-05T16:19:17Z"}],"visa":[{"country":"GB","licensed_sponsor":true,"evidence":"Licensed UK visa sponsor (Skilled Worker)","filings_12m":null,"filings_prev_12m":null,"green_card_filings_12m":null,"median_offered_wage_usd":null,"route":"Skilled Worker","cap_exempt":false,"checked_at":"2026-10-22T06:27:10+00:00","sources":["UK Home Office: register of licensed sponsors (workers)"],"filings_for_role_12m":0}],"liveness":{"score":45,"band":"ok","label":"Likely open","p_open":1,"p_active":0.744,"p_room":0.6,"age_days":77,"expected_fill_days":81,"reasons":["conf:0","velocity","win:late","crowd:brand"],"computed_at":"2026-10-22T06:10:10Z"},"pay":null,"html_url":"https://alion.io/job/sonarsource-ai-researcher-post-training","json_url":"https://alion.io/job/sonarsource-ai-researcher-post-training.json","meta":{"generated_at":"2026-10-22T10:31:31Z","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":7764,"day_limit":null,"remaining_today":null,"minute_limit":300,"resets_at":"2026-10-23T00:00:00Z"}},"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":4925},"rest":"https://alion.io/mcp/rest/get_company?id=4925"},"human":"https://alion.io/catalog?offer=company.slices&for=job%2Fsonarsource-ai-researcher-post-training"},{"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%2Fsonarsource-ai-researcher-post-training"},{"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%2Fsonarsource-ai-researcher-post-training"},{"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/sonarsource-ai-researcher-post-training\", \"note\": \"what you need it for\"}"},"human":"https://alion.io/catalog?offer=company.verify&for=job%2Fsonarsource-ai-researcher-post-training"}]}