Machine Learning Engineer

usepassionfruit.com; Greater London; On-site; GBP 70,000 - 100,000; Full time

Job summary

Passionfruit in London is seeking a Machine Learning Engineer to design, build, and ship production ML systems powering our marketing-focused platform. The role emphasizes real-time chat, workflow automation, and autonomous agents, with ownership and meaningful user impact.

You’ll work in a hybrid setup (London, Chancery Lane) with typical hours 9-6pm, collaborating closely with product and engineering to deliver reliable AI in a fast-moving environment.

Qualifications

• Strong experience building and shipping ML systems in production.
• Hands-on experience with LLMs, RAG, agents, or workflow-driven AI systems.
• Solid engineering fundamentals (Python, APIs, data pipelines, evaluation).
• Comfort working in a fast-moving product environment.

Responsibilities

• Develop and deploy ML/LLM systems for marketing workflows.
• Build agentic systems with memory, tools, and orchestration.
• Integrate models with live data sources (ads platforms, CRM, analytics).
• Improve retrieval, evaluation, and fine-tuning on marketing data.
• Collaborate with product and engineering to ship reliable, user-facing AI.

Skills

Production ML systems

LLMs / RAG / agents

Python

Data pipelines

APIs

Tools

Python

Job description

Passionfruit launches PIPAI Learn More Passionfruit careers

Machine Learning Engineer

Hybrid Full-Time

About Passionfruit

We’re building AI-native operations for marketing teams - automating the work that slows them down, from campaign briefs and performance reporting to creative review, compliance workflows, and paid media analysis. Our platform is purpose-built for marketing, trained on real marketing workflows and deeply integrated with ad platforms, CRMs, brand assets, and analytics tools.

As an ML Engineer, you’ll design, build, and ship production ML systems that power our core product and agent ecosystem - from real-time chat and workflow automation to autonomous agents like daily performance briefings and competitor tracking.

What you’ll work on

• Develop and deploy ML/LLM systems for marketing-specific workflows (reporting, analysis, review, compliance)
• Build agentic systems with persistent memory, tool use, and workflow orchestration
• Integrate models with live data sources (Google Ads, GA4, Meta Ads, CRM, analytics)
• Improve retrieval, evaluation, and fine-tuning on marketing-domain data
• Collaborate closely with product and engineering to ship reliable, user-facing AI

What we’re looking for

• Strong experience building and shipping ML systems in production
• Hands-on experience with LLMs, RAG, agents, or workflow-driven AI systems
• Solid engineering fundamentals (Python, APIs, data pipelines, evaluation)
• Comfort working in a fast-moving product environment
• Bonus: experience with marketing, ads platforms, or analytics data. Also ideal if you’ve worked with Elixir.

You’ll have meaningful ownership, real user impact, and the chance to define how AI actually works inside modern marketing teams.

Working hours and location

Location: London, Chancery Lane

Hours: 9-6pm