Senior Machine Learning Engineer
At a glance
Senior Machine Learning Engineering role at Relay Technologies. London · full-time · no salary stated · we estimate £125,500–£152,500.
Relay Technologies has not published a salary for this role. The figure below is our estimate, not theirs.
aimlroles summary, based on the employer's posting.
What you'll do
- Take models from training workflows into live services, then track the business results they produce
- Shape the ML platform by improving model serving, reusable components and shared release standards
- Add integration and system checks to training workflows, alongside automated releases and drift alerts
- Work with data scientists to replace existing processes and test the effect on network performance
What you bring
- At least two years deploying and supporting machine learning models in production
- Four or more years of software development experience on high-performing teams
- You can work through unfamiliar code and languages to bring a model into a live system
Who this fits
This senior role suits an engineer who takes models through production and prefers automating repeat work. You’ll work closely with data scientists and measure changes against their real-world network impact. The role is based in London, United Kingdom.
From the employer
Relay is fundamentally reshaping how goods move in an online era. Backed by Europe’s largest-ever logistics Series A ($35M) led by deep-tech investors Plural, and a recently closed Series B ($95M), Relay is scaling faster than 99% of venture-backed startups. We're assembling the most talent-dense team the logistics industry has ever seen
Relay’s Mission is to free commerce from friction. Today, high delivery costs act as a hidden tax on e-commerce, quietly shaping what can be sold online and limiting who can participate. We envision a world where more goods move more freely between more people, making the online shopping experience seamless and accessible to everyone.
THE TEAM
• ~160 people, around half in engineering, product and data
• 45+ advanced degrees across computer science, mathematics and operations research
• Thousands of data points captured, calculated, analysed and predicted for every single parcel we handle
• An intellectually vibrant culture of first‑principles thinking, tight feedback loops and relentless experimentation
Every parcel Relay handles is touched by ML. We recommend and optimise route assignment, predict delivery durations, estimate parcel dimensions and weight, detect objects in images on device, forecast demand and decide network handovers. That's 10+ models running in the critical path of a live logistics network where quality is non-negotiable.
ML Stack Highlights
Python and Rust. We keep things simple but use the right tool for the job
Rust with ONNX in-process model execution where throughput is critical
Chalk.ai as our Feature Store
GCP Agent Platform Endpoints for model serving
Cloud-native on GCP. Services run on Kubernetes, with extensive use of BigQuery
The Opportunity
As a Senior Machine Learning Engineer at Relay, you'll:
Own critical part of ML: productionising of our models end-to-end, from training pipeline through live integration to measured business impact.
Build and mature our ML Platform. Evolve the model serving architecture, expand reusable components adoption and set the standards for how Relay ships ML org-wide.
Strengthen existing models by architecting integration and system testing within training pipelines, automated releases and drift monitoring.
Launch completely revamped processes side by side with data scientists and measure their real-world impact on the network.
We're looking for candidates who…
Have at least two years deploying and operating models in production and four years building software on high-performing teams.
Are comfortable diving into unfamiliar codebases and languages to ship a model into a live system.
Prefer building the automation that removes manual labour over repeating it.
Who Thrives at Relay?
Aim with Precision: You define problems clearly and measure your impact meticulously.
Play to Win: You chase bold bets, tackle the hard stuff, and view constraints as fuel, not friction.
1% Better Every Day: You believe that small, consistent improvements lead to exponential growth. You move quickly, deliver results, and learn from every experience.
All In, All the Time: You show up and step up. You take ownership from start to finish and do what it takes to deliver when it counts.
People-Powered Greatness: You invest in your teammates. You give and receive feedback with care and candour. You build trust through high standards and shared success.
Grow the Whole Pie: You seek out win-win solutions for merchants, couriers, and our customers, because when they thrive, so do we.
If these resonate, and you combine strong technical fundamentals with entrepreneurial drive, let’s connect.
Relay is an equal-opportunity employer committed to diversity, inclusion, and fostering a workplace where everyone thrives.