At a Glance
- Tasks: Design and build cutting-edge reinforcement learning environments and data pipelines.
- Company: Join a dynamic AI startup backed by top investors, fostering innovation and collaboration.
- Benefits: Meaningful equity, flexible work environment, and the chance to make a real impact.
- Other info: Ideal for those who thrive in resource-constrained settings and love solving complex problems.
- Why this job: Be part of a small team where your contributions directly shape the future of AI.
- Qualifications: Experience in building RL environments and a strong background in AI applications.
The predicted salary is between 60000 - 80000 £ per year.
We’re building AI to make humans irreplaceable. Ethos is the platform that matches human expertise to paid opportunities, from advisory roles to consulting opportunities and full-time positions, backed by a16z, General Catalyst and other top investors. Small team. Flat hierarchy. High ownership. We build first, experiment rapidly, and automate every process after mastering it once. We lead with taste, clarity, and empathy. We are looking for winners with a heart of gold.
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
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
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.
Reinforcement Learning Engineer employer: Ethos
At Ethos, we pride ourselves on being an exceptional employer that fosters a culture of innovation and collaboration. Our small, flat team structure empowers you to take ownership of your projects while working in a dynamic environment that values rapid experimentation and personal growth. With meaningful equity opportunities and a commitment to making a positive impact, joining us as a Reinforcement Learning Engineer means being part of a mission-driven company where your contributions truly matter.
StudySmarter Expert Advice🤫
We think this is how you could land Reinforcement Learning Engineer
✨Tip Number 1
Network like a pro! Reach out to people in the industry, attend meetups, and connect with potential colleagues on LinkedIn. We all know that sometimes it’s not just what you know, but who you know that can land you that dream role.
✨Tip Number 2
Show off your skills! Create a portfolio showcasing your projects, especially those related to reinforcement learning. We want to see what you can do, so make sure your work is easily accessible and highlights your hands-on experience.
✨Tip Number 3
Prepare for interviews by practising common questions and scenarios specific to RL environments. We recommend doing mock interviews with friends or using online platforms to get comfortable discussing your experiences and problem-solving approaches.
✨Tip Number 4
Don’t forget to apply through our website! It’s the best way to ensure your application gets seen by the right people. Plus, we love seeing candidates who take the initiative to engage directly with us.
We think you need these skills to ace Reinforcement Learning Engineer
Some tips for your application 🫡
Show Your Passion for AI:When writing your application, let your enthusiasm for AI and reinforcement learning shine through. We want to see that you’re not just ticking boxes but genuinely excited about the work we do at StudySmarter.
Highlight Relevant Experience:Make sure to showcase any hands-on experience you've had with building RL environments or generating data for post-training. We love seeing concrete examples of your past work that align with what we’re looking for.
Be Yourself:We value authenticity, so don’t be afraid to let your personality come through in your application. Share your unique perspective and how it can contribute to our mission of making humans irreplaceable.
Apply Through Our Website:For the best chance of getting noticed, make sure to apply directly through our website. It helps us keep track of applications and ensures you’re considered for the role you’re excited about!
How to prepare for a job interview at Ethos
✨Know Your Reinforcement Learning Stuff
Make sure you brush up on your reinforcement learning concepts and frameworks. Be ready to discuss your hands-on experience with building RL environments and generating data for post-training workflows. They’ll want to see that you can talk the talk and walk the walk!
✨Show Off Your Startup Experience
Since this role is in a startup environment, be prepared to share specific examples of how you've thrived in resource-constrained settings. Highlight times when you took ownership of projects and shipped products, as this will resonate well with their flat hierarchy and high ownership culture.
✨Demonstrate Your Generalist Instincts
They’re looking for someone who can solve problems across the stack. Be ready to discuss how you’ve tackled challenges beyond your usual lane, whether it’s backend, infrastructure, or ML tooling. Show them you’re adaptable and eager to learn!
✨Emphasise Empathy and Teamwork
Given their focus on taste, clarity, and empathy, it’s crucial to convey your ability to work well with others. Share examples of how you’ve collaborated with diverse teams and how you value input from different perspectives. This will show you align with their company ethos.
