Machine Learning Engineer (£70k+ + Equity) at Social-impact AI startup backed by founders of Tide and Mumsnet

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Job Title

Machine Learning Engineer (On-Device & Multimodal)

Salary

£70k+ + Equity

Company Description

Social-impact AI startup backed by founders of Tide and Mumsnet

Job Description

You will own the end-to-end detection pipeline for a pioneering child-safety app, developing on-device ML models that protect children from harmful content in real-time. By optimizing YOLO-style detection and transformer classifiers for mobile hardware, you will build a privacy-first safety layer that works across every application on a child's smartphone.

Location

London, UK

Why this role is remarkable

• Work on a high-impact product with a genuine social mission, supported by high-profile figures like Sir Tim Berners-Lee and Hugh Grant.
• Own the entire ML capability from strategy to deployment, reporting directly to the founder with significant influence over technical direction.
• Solve complex on-device inference challenges through a unique partnership with Mumsnet and Nothing Technology to launch child-safe hardware.

• Design and train computer vision and NLP models to detect harmful content across varied UI contexts and video feeds.
• Optimize model performance for low-latency, on-device execution using quantization, TFLite, and ONNX Runtime on Android devices.
• Build robust evaluation suites and error-analysis workflows to minimize false positives while maintaining high recall for critical safety scenarios.

• 2+ years of experience in applied ML or research, ideally with a background in object detection (YOLO) and transformer architectures (ModernBERT/RoBERTa).
• Proven ability to ship production-grade ML systems, balancing scientific rigor with the practical trade-offs of a fast-moving startup environment.
• Hands-on expertise in model optimization and threshold tuning, specifically for on-device inference where memory and speed are constrained.

Ok, I'll go first. I'm Jack, an AI that gets to know you on a quick call, learning what you're great at and what you want from your career. Then I help you land your dream job by finding unmissable opportunities as they come up, supporting you with applications, interview prep, and moral support.

And I'm Jill, an AI Recruiter who talks to companies to understand who they're looking to hire. Then I recruit from Jack's network, making an introduction when I spot an excellent candidate.

Next steps

Step 1. Visit the job listing.

Step 2. Click 'Talk to Jack', or go straight there: https://www.jackandjill.ai/jobs/machine-learning-engineer-70k-equity-at-social-impact-ai-startup-backed-by-found-99701bd2-fb48-429c-9887-de826de8f420?utm_source=linkedin&utm_medium=job_post&utm_campaign=featured_role_99701bd2-fb48-429c-9887-de826de8f420

Step 3. Talk to Jack so he can understand your experience and ambitions.

Step 4. Jack will make sure Jill (the AI agent working for the company) considers you for this role.

Step 5. If Jill thinks you're a great fit and her client wants to meet you, they will make the introduction.

Step 6. If not, Jack will find you excellent alternatives. All for free.

We never post fake jobs

This isn't a trick. This is an open role that Jill is currently recruiting for from Jack's network.

Sometimes Jill's clients ask her to anonymize their jobs when she advertises them, which means she can't share all the details in the job description.

We appreciate this can make them look a bit suspect, but there isn't much we can do about it.

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