Senior AI Engineer - LLM & Conversational AI

JOB TITLE: Senior AI Engineer - LLM & Conversational AICompany: Ethical Den

Location: Kolkata, West BengalWork Mode: On-site only

Employment Type: Full-timeExperience: 4 to 7+ yearsOpenings: 1Joining: Immediate to 30 days preferredABOUT THE ROLEEthical Den is looking for a Senior AI Engineer to join our in-house AI research and product engineering team.You will work on a confidential technology initiative involving large language models, conversational AI, model adaptation, AI agents and real-time AI systems.This is a hands-on engineering position with technical ownership responsibilities.We are not looking for someone whose experience is limited to prompt engineering or basic integrations with commercial AI APIs.Detailed information about the project will be shared with shortlisted candidates at the appropriate stage of the hiring process and will be subject to confidentiality requirements.KEY RESPONSIBILITIES

• Design and improve LLM-based AI systems.
• Evaluate suitable open-source and self-hosted language models.
• Fine-tune and adapt language models for specialised requirements.
• Develop conversational-state and contextual-memory systems.
• Design intelligent routing between different AI models and workflows.
• Build structured-output and tool-calling systems.
• Work closely with engineers developing retrieval and agent systems.
• Improve hallucination control and unsupported-answer behaviour.
• Design model evaluation and regression-testing frameworks.
• Develop reliable correction, fallback and recovery behaviour.
• Optimise responses for real-time AI applications.
• Work with inference engineers to reduce latency and compute requirements.
• Evaluate model quality against latency and infrastructure cost.
• Participate in architecture decisions and technical reviews.
• Mentor junior engineers and interns.
• Remain actively involved in coding, experimentation and debugging.REQUIRED SKILLS
• Python
• PyTorch
• Hugging Face Transformers
• LLM inference
• Fine-tuning
• LoRA / QLoRA
• Model quantisation concepts
• Conversational AI
• Function calling / tool calling
• Structured outputs
• RAG fundamentals
• Embeddings
• Vector databases
• Model evaluation
• Linux
• Git
• REST APIs
• WebSocket-based systemsCandidates should understand concepts such as:
• Time to first token
• Throughput
• Model latency
• Context management
• GPU memory utilisation
• Quantisation
• Model servingGOOD TO HAVE
• Experience deploying self-hosted LLMs
• Multilingual NLP experience
• vLLM or similar inference frameworks
• Model distillation
• Agentic AI systems
• Production AI experience
• Technical leadership experience
• Open-source AI contributionsEDUCATIONAL QUALIFICATIONPreferred:B.Tech/B.E./M.Tech/MCA/M.Sc. in Computer Science, Artificial Intelligence, Machine Learning, Data Science or a related field. (We are not much concerned about your college degree)Strong hands-on experience, research work or significant open-source contributions may compensate for a different academic background.WHO SHOULD APPLYCandidates who have personally built, fine-tuned, deployed or materially improved AI/ML systems.WHO SHOULD NOT APPLYCandidates whose experience is primarily limited to:
• Prompt engineering
• Basic OpenAI/Claude/Gemini API integration
• Simple chatbot development
• No-code AI tools
• Management roles without hands-on AI engineeringAPPLICATION DETAILSPlease include:
• Updated CV
• Current location
• Current CTC
• Expected CTC
• Notice period
• GitHub / Hugging Face / portfolio links
• Relevant publications, if applicable
• Brief description of the most technically challenging AI project you have worked onCONFIDENTIALITYThis position involves work on a confidential internal technology initiative. Selected candidates will be required to comply with Ethical Den's confidentiality and intellectual-property policies. Detailed project information will be disclosed only at the appropriate stage of the hiring process.