Founding ML Engineer (Spectrum)

JetBrains; Greater London; On-site; GBP 70,000 - 100,000; Full time

Benefits offered by this job

Competitive salary

Generous runway with startup autonomy

JetBrains benefits

Job summary

JetBrains is looking for a top-class ML Engineer to shape the future of software development through AI and ML technologies. You will define the research agenda and own the AI engineering stack. Responsibilities include designing LLM solutions and establishing MLOps practices. The ideal candidate should have at least five years of experience in ML/AI systems, hands-on LLM experience, and strong Python skills. We offer a competitive salary and startup-like autonomy.

Qualifications

• At least five years of experience in ML/AI systems.
• Two years focused on LLMs and generative AI.
• Strong Python skills; Kotlin knowledge is a plus.

Responsibilities

• Design ML/LLM solutions for data ingestion and knowledge extraction.
• Create datasets and metrics for system improvements.
• Establish MLOps practices, including orchestration and observability.

Skills

Machine Learning

LLM (Large Language Models)

Python

Prompt Engineering

Ontologies

Tools

Vector Databases

LangChain

RAG Patterns

Job description

Spectrum collects data from an organization’s code, docs, and issues, and organizes knowledge in a unified ontology that AI agents can efficiently search through and reason over. We aim to revolutionize the semantic layer space for software-building organizations and move beyond specs that fall out of sync with code, introducing a living spec – one that’s extracted from the whole system and used to keep it aligned. Spectrum is meant to be the single source of truth for all product and architectural knowledge.

Overview

Spectrum is a resident of JetBrains' startup incubator, with startup speed and autonomy, and backed by 25 years of developer tooling expertise. We are looking for a top-class ML Engineer who will help us shape the future of software development. You will own our AI and ML engineering stack and help define the research agenda for our team. Your technical vision and design decisions will directly shape the product and determine its success.

Responsibilities

• Designing and building the ML/LLM solution for data ingestion, knowledge extraction, retrieval, and subsequent reasoning.
• Creating the datasets, metrics, and pipelines that drive measurable improvements across the system.
• Architecting and improving agents for context retrieval, knowledge extraction, and data alignment, which includes prompt engineering, model selection, and inference optimization.
• Establishing MLOps practices, including orchestration, observability, and experiment tracking.
• Collaborating with the engineering team on system design and with JetBrains Research on the research agenda.
• Defining hiring criteria, growing the ML team, and shaping the ML team culture.

Qualifications

• A proven track record as an ML/AI Lead.
• At least five years of experience in ML/AI systems, with at least two years focused on LLMs and generative AI.
• A deep understanding of the LLM ecosystem, including model architectures and fine-tuning approaches.
• Hands-on experience with:
  • Prompt engineering and LLM pipeline design, including evaluation.
  • Agentic frameworks such as LangChain, LlamaIndex, LangSmith, smolagents, or an equivalent.
  • Vector databases and retrieval-augmented generation (RAG) patterns.
  • Deploying and scaling LLM-powered applications using APIs (e.g. OpenAI or Anthropic) or open-source models.
• Strong Python skills – Kotlin knowledge would be a plus.
• Excellent communication skills, with the ability to explain complex technical concepts to diverse audiences.
• Proficiency in English, both written and verbal.

Our Ideal Candidate Would Have

• Experience with ontologies, knowledge graphs, or graph-based reasoning.
• Experience in early-stage startups – you enjoy the zero-to-one phase.
• The ability to think strategically about product-led AI, beyond just training models in isolation.
• A background in code analysis, developer tools, or software engineering research.
• Experience with multi-agent systems or complex agentic workflows.
• Actively contributed to relevant open-source projects or publications.

Benefits

• A competitive salary and JetBrains benefits.
• A generous runway and corporate resources with startup autonomy.

Equal Opportunity

We are an equal opportunity employer. We know great ideas can come from anyone, anywhere. That’s why we do our best to create an open and inclusive workplace – one that welcomes everyone regardless of their background, identity, religion, age, accessibility needs, or orientation.

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