Senior AI Engineer

Job Description

Your role in the company

We’re seeking a Senior AI Engineer with a strong background in machine learning and modern web development. You’ll play a key part in architecting and building a complex backend that intertwines AI at nearly every step of its architecture. You’ll design and implement data pipelines, develop Retrieval-Augmented Generation (RAG) solutions, and guide the evolution of our AI models—from fine-tuning existing frameworks to training cutting-edge models from scratch. Your work will directly inform how our platform processes, interprets and acts on the vast spectrum of data we collect.

What you will do

Main responsibilities:

• Architect & Develop: Design, implement, and maintain Python-based services that power our AI-driven platform.
• Advanced RAG Pipelines: Build and refine Retrieval-Augmented Generation workflows that integrate multiple data sources for highly contextual AI response.
• Model Fine-Tuning & Training: Lead efforts to adapt open-source models to our unique data and use cases and eventually develop proprietary models from scratch as the platform grows.
• Data Management and Engineering: Create and optimize robust data pipelines for collecting and processing large volumes of data.
• Full Backend Ownership: Take part in the complete backend ecosystem—everything from database modeling and API design to integration with frontend interfaces.
• Cross-Functional Collaboration: Work closely with data scientists, product managers, and UX teams to align our technical solutions with user needs and business goals.
• Continuous Innovation: Stay on top of the latest AI research and tools, evaluating their applicability to Flux AI’s evolving platform needs.

What we need

Our dream teammate possesses certain skillset:

Essential requirements:

• Strong Python Skills: Solid background in Python-based OOP (5+ years) and backend development, with familiarity in frameworks like TensorFlow, PyTorch, or similar.
• AI/ML Savvy: Hands-on experience with machine learning (NLP, classification, regression, recommendation systems), semantic analysis, RAG, model finetuning, and training.
• Data Management: Experience architecting ETL/ELT pipelines, handling data orchestration, and ensuring data quality for downstream AI applications.
• Strong Communication: Fluent in English with an ability to articulate complex technical concepts to non-technical audiences.
• Proactive Mindset: A passion for innovation and a knack for translating big-picture visions into tangible, high-quality deliverables.

Requirements considered an advantage:

• Experience with various GenAI APIs.
• Familiarity with tools such as lightllm, langchain, and lama-index.
• Experience with frameworks like Dash and Streamlit.

Our benefits

We offer various benefits:

Personal benefits:

• Career path and salary updates.
• Additional health insurance.
• Multisport card.
• Additional paid leave after 3rd year.
• Company psychologist.
• Christmas bonus.
• Baby bonus.
• Yearly bonus for sport equipment.
• Bonus for bicycle.

Team and workplace benefits:

• Office in downtown Sofia.
• Environment with highest standards.
• Young and passionate team.
• Regular team and company events.
• Company training activities.
• Monthly teambuildings.

The Process

The steps you need to complete:

• Screening – Each resume is personally evaluated by an HR representative based on various criteria. During this initial step only the shortlisted candidates are contacted.
• Test – One or two short online questionnaires taking ≤ 1 hour to complete.
• HR interview – A behavioral interview with a recruiter that takes ≈30 minutes and stresses on motivational and success factors.
• Assignment – Online assignment with strict requirements, testing the expected capabilities and creative thinking.
• Final Interview – Led by the hiring manager for the team, the interview discusses the job requirements and team fit.