About Relling: Relling (YC S25) builds ready-to-deploy robot workcells for US manufacturers. We design and test in San Francisco and put systems to work on factory floors. This is a full-time, in-person role in Potrero Hill, San Francisco. What you'll do: Build, test and improve mechanical and electromechanical systems for robotic workcells. Work across mechanical, electrical and software interfaces during cell bring-up. Diagnose failures under load, test fixes and document what works. What we're looking for: Experience building and testing physical systems, with clear ownership you can explain end to end. Strong mechanical and electromechanical fundamentals and sound engineering judgment. A practical approach to debugging: calculations, measurements, root causes and validation. How to apply: Apply with your resume and a short description of a system you built or shipped. Project links are optional. Tell us what you owned, what failed and how you tested the fix.