AI Researcher - Post-Training (f/m/d)

About the Position

AI Researcher - Post-Training (f/m/d)

Location: Bochum, Germany

Employment Type: Full-Time, On-site

Salary Range: €90,400 - €166,800 a year

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About the Company

Sonar is at the forefront of agent-centric software development, specializing in AI code verification and governance. We empower over 75% of the Fortune 100 to build reliable, secure, and maintainable software. Our products, including SonarQube and SonarQube Foundation Agent, are trusted by industry giants like Nvidia, ServiceNow, and Goldman Sachs.

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About the Role

At Sonar, we are seeking an ambitious senior researcher to join our cross-disciplinary team. You will be instrumental in developing the next generation of solutions for enterprise-grade coding agents and models. Your work will combine Sonar’s expertise in static analysis with advanced techniques in large language model post-training.

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Responsibilities

• Outcome Driven Development: Collaborate with a team to develop and implement advanced products that enable customers to post-train models for their agentic coding practices.
• Translate Prototypes to Products: Work closely with researchers, engineers, and MLOps to design hypotheses, iterate proofs-of-concept, and develop successful prototypes into cutting-edge products.
• Subject Matter Expert: Contribute and discuss ideas within our cross-disciplinary team, driving the next generation of coding model post-training for enterprises.
• Spearhead Research & Innovation: Stay updated with the latest LLM and agentic developments, and explain complex technical details to both technical and non-technical audiences.

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Requirements

• Education: Advanced academic background (Master’s or PhD) in Computer Science, Machine Learning, or a related quantitative field.
• Experience: 4+ years of industry experience in machine learning, with a solid understanding of modern software engineering practices and tools.
• Skills:
  • Fluency with Python and core ML frameworks.
  • Expertise in post-training of large language models, including:
    • Policy optimization algorithms (e.g., GRPO, PPO)
    • Verifier-based RL frameworks (RLVR)
    • Supervised fine-tuning (SFT)
    • Data-centric AI methods, including synthetic data and curation
    • Parameter-efficient fine-tuning (PEFT)
    • Preference and Safety Alignment
  • Experience with Rust or any of SonarQube’s flagship languages (C#, C++, JS/TS, Java) is a plus.
• Communication: Excellent communication skills in English and the ability to explain complex scientific topics clearly and concisely.

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We Offer

• Competitive salary range
• Opportunity to work at the forefront of AI
• Collaborative and inclusive work environment
• Relocation support for the right candidate

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About the Company

At Sonar, we value diversity, equity, and inclusion. We are committed to fostering a diverse and inclusive work environment where everyone feels valued and empowered to contribute their best. We are proud to be an equal opportunity employer and welcome all qualified applicants, regardless of race, color, religion, gender, gender identity or expression, sexual orientation, national origin, genetics, disability, age, or veteran status.

If you need any accommodation, please reach out to us at [email protected].

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