Senior Back-End Software Engineer, Infra

About the role

We’re scaling quickly, and the foundation that supports our product needs to scale with it. We’re hiring a Senior Back-End Software Engineer to join our Infra team and take ownership of our Rails stack — keeping it modern, efficient, and built to last. You’ll help shape internal tooling, reduce third-party dependencies, and ensure our infrastructure is ready for the next stage of growth.

What you’ll be doing

• Maintain and modernize our Rails stack, including dependency upgrades, performance optimization and security enhancement
• Build internal tools, SDKs, and libraries to improve developer experience and infrastructure scalability
• Partner with your front-end counter-parts and SREs to support observability, performance, and reliability initiatives
• Identify opportunities to build in-house systems that reduce reliance on costly third-party services
• Contribute to architectural decisions that improve the performance, security and cost-efficiency of our platform

What you’ll need to be successful

• Strong alignment with our values (find our values on our career page if you haven’t read up on them yet)
• You are proficient in English (spoken, written, and reading) at a CEFR Level C2 / ILR Level 5
• Deep expertise with Ruby on Rails, with an emphasis on infrastructure and architectural improvements
• Solid experience working with MySQL and/or Postgres
• A strong track record of improving performance, scalability, and system reliability
• 5+ years of experience in a back-end engineering role, ideally focused on infrastructure or platform systems
• Comfortable working autonomously in a fast-paced, fully remote environment

Bonus points

• You’ve helped scale an early-stage product to 1M+ monthly active users.
• Experience with front-end technologies (especially React)
• You’ve built internal tooling or SDKs for use across engineering teams
• Experience reducing infrastructure or tooling costs through in-house solutions

What We Have to Offer

• Fully remote: work from anywhere in the world!
• Autonomy and trust to do your job: we care about outcomes over everything else.
• Paid time away: all employees are given 35 days of PTO annually. We also offer a paid sabbatical after 5 years.
• Generous U.S. benchmarked compensation and startup equity no matter where you are in the world.
• Awesome medical coverage with 100% coverage for you and your family, or medical reimbursement options where applicable!
• Parental leave for parents expanding their family, or just starting one.
• Home office stipend to help you get up and running.
• Learning & development stipend to help you level up your professional skills.
• Annual bonus potential for roles that don’t already receive variable income or commission.
• Company retreats: Twice a year, the Circle team gets together for a fully paid company retreat in incredible places around the world!