At a Glance
- Tasks: Design and build RL environments and data pipelines for AI model training.
- Company: Ethos, a pioneering AI platform backed by top investors.
- Benefits: Meaningful equity, competitive salary, and a chance to shape the future of AI.
- Other info: Dynamic startup environment with opportunities for real ownership and impact.
- Why this job: Join a mission to make humans irreplaceable in the AI landscape.
- Qualifications: Experience in RL environments and a strong background in AI applications.
The predicted salary is between 63000 - 77000 £ per year.
About Ethos
We’re building AI to make humans irreplaceable. Ethos is the platform that matches human expertise to paid opportunities, from AI model training to advisory roles and full-time positions, backed by a16z, General Catalyst and other top investors.
What You’ll Work On
- Designing and building RL environments and data generation pipelines that feed into post-training workflows
- Agentic infrastructure that sources, screens, and routes domain experts at scale
- Evaluation frameworks to close the loop between data quality and model performance
This is an early-stage role with meaningful equity. If you’ve built things that matter at companies that didn’t have all the answers, we’d love to talk.
Key Requirements
- Hands-on experience building RL environments or generating data for post-training (RLHF, RLAIF, preference data, evals) — this is central to the role
- Startup experience — you’ve shipped in resource-constrained environments and taken real ownership
- Strong background building AI/agentic applications (LLM pipelines, tool use, evals)
- Generalist instincts - you’d rather solve the problem than protect your lane
- Comfortable across the stack: backend, infra, and ML tooling
RL Engineer in London employer: Ethos
Ethos is an exceptional employer that prioritises both technical excellence and personal wellbeing, making it an ideal place for a Senior Mechanical Design Engineer to thrive. With a flexible working model, including Flexible Fridays and a 9-day fortnight, employees enjoy a healthy work-life balance while benefiting from clear progression pathways and opportunities for professional development. The Birmingham hub offers a collaborative environment where you can work alongside experienced engineers on cutting-edge data centre projects across the EMEA region.
StudySmarter Expert Advice🤫
We think this is how you could land RL Engineer in London
✨Join Local Tech Meetups
Get out there and mingle with fellow developers by joining local tech meetups. It’s a fantastic way to meet people who might be working at Ethos or know someone who does. Plus, you can pick up some trendy tech skills and trends while you're at it!
✨Contribute to Open Source Projects
Show off your coding chops by jumping into open-source projects. Not only does this give you practical experience, but it also gets you noticed in the dev community. You'll create a killer portfolio that speaks volumes about your skills to Ethos.
✨Tap into Online Developer Communities
Don’t underestimate the power of online developer communities like GitHub, Stack Overflow, and even Reddit. Participate in discussions, share your projects, and build your visibility. We can often find opportunities through these channels that can lead to a full-time gig at companies like Ethos.
✨Explore Job Boards Specifically for Tech Roles
Keep your eyes peeled on job boards that focus on tech roles. Sites like TechCareers or Stack Overflow Jobs can often have listings for companies like Ethos that might not show up on broader job sites. Make it a habit to check these regularly, and don’t hesitate to apply directly through our website!
We think you need these skills to ace RL Engineer in London
Some tips for your application 🫡
Show off your coding skills:When applying for a software engineering role, it's super important to showcase your coding skills. Make sure your CV includes your tech stack, any relevant programming languages you’re comfortable with, and examples of projects you've worked on. If you have a GitHub profile, link it up! We love to see code in action.
Tailor your portfolio:For a full-time role, we’d expect to see some solid examples of your work in your portfolio. Make sure to include at least two or three projects that highlight your problem-solving skills and your ability to work with different technologies. Focus on the projects that are most relevant to the position at Ethos.
Craft a killer cover letter:Your cover letter is your chance to stand out—make it personal! Explain why you want to work at Ethos and how your skills align with the role. Show us your passion for software development. We dig enthusiastic candidates who understand the value of collaboration and continuous learning!
Be clear and concise:When it comes to writing your CV and cover letter, clarity is key. Avoid jargon that could confuse us and stick to simple, direct language. Highlight your achievements with quantifiable results where possible, and keep everything easy to read. A well-organised application goes a long way!
How to prepare for a job interview at Ethos
✨Brush Up on Your Coding Skills
For a full-time software engineering role, it's crucial that we stay sharp with our coding abilities. Expect technical questions that might involve solving problems on the spot or discussing algorithms. Practise on platforms like LeetCode or HackerRank to get comfortable with the types of questions that often come up.
✨Know Your Tools and Frameworks
Make sure we’re well-acquainted with the tools and technologies listed in the job description. Familiarise ourselves with any specific frameworks or programming languages mentioned. If Ethos uses React or Node.js, for instance, be ready to discuss how we’ve used them in previous projects or coursework.
✨Showcase Your Projects
Bring along a portfolio that highlights our best work. This could be code samples, GitHub repositories, or any side projects we’ve built. Make sure we can talk through our thought process for each project, especially the challenges we faced and how we solved them—this shows our problem-solving skills in action.
✨Prepare for Behavioural Questions
While technical skills are key, full-time positions also require cultural fit. Be ready to discuss our previous experiences and how we handle teamwork, conflict, and deadlines. Brush up on the STAR method—Situation, Task, Action, Result—to clearly articulate our past experiences when discussing how we've contributed to a team.
