Senior Software Engineer

About CircleCI Engineering

At CircleCI, our engineering teams are the driving force behind the platform trusted by developers worldwide to build, test, and deploy their code with confidence. We operate at a massive scale, processing over 50 million builds per month for organizations ranging from innovative startups to industry-leading enterprises. Our platform sits at a critical intersection in the software development lifecycle, where reliability, performance, and user experience directly impact the productivity of development teams around the globe.

As we continue to innovate, we're increasingly leveraging AI to transform the software delivery experience. From intelligent test selection that reduces build times, to predictive analytics that prevent pipeline failures, to AI-powered developer tools that streamline workflows, we're using machine learning and artificial intelligence to solve complex engineering challenges. We believe AI represents the next frontier in CI/CD, enabling smarter, more efficient, and more reliable software delivery pipelines.

Your work at CircleCI directly impacts how software is delivered across the industry. When you contribute to our systems—whether they're customer-facing interfaces, core platform capabilities, or developer tools—you're helping teams worldwide ship better code faster and with greater confidence. The systems you'll help build enable innovation across the entire software industry, making you an essential part of the modern development ecosystem.

Team-Agnostic Placement

We hire team-agnostically at CircleCI, meaning we don’t recruit for a single team from the start. Instead, we get to know each candidate through the interview process and then place them on the team where their strengths, interests, and experience will make the greatest impact. This approach allows us to be thoughtful about matching engineers with the right challenges, and it gives new hires a stronger foundation for long-term success and growth. It’s part of our commitment to building balanced, high-performing teams that are set up to thrive.

By carefully matching your skills to the right team, we ensure you can make the most meaningful impact on systems that are critical to the success of development teams worldwide.

What You’ll Do:

• Design and build reliable, observable, zero-downtime distributed systems that serve millions of builds across thousands of customers.
• Collaborate with cross-functional teams to shape and refine foundational capabilities.
• Own your work from concept to deployment and beyond—digging into production issues using tools like Honeycomb, Datadog, Grafana, and Rollbar to ensure system health.
• Write clear, maintainable, and well-documented Go code, with observability and long-term maintainability built in.
• Participate in architectural decisions and technical strategy development.
• Lead complex projects and initiatives from inception to completion.
• Mentor junior and mid-level engineers and provide technical guidance to the team.
• Contribute to a culture of continuous improvement, helping your team and our customers succeed.
• Continue your professional growth through increased technical scope, leadership opportunities, and strategic impact, supported by mentorship from experienced leaders and exposure to complex engineering challenges across the organization.

What You’ll Bring:

• 5+ years of professional software development experience, with a strong emphasis on backend systems.
• Deep proficiency in Go, and comfort working in a polyglot environment that may include JavaScript, Clojure, and bash.
• Proven experience building and maintaining production-quality distributed systems at scale.
• Strong software testing skills with experience writing comprehensive unit, integration, and end-to-end tests that ensure code quality and reliability.
• Familiarity with Kubernetes and modern deployment practices.
• A production-first mindset—you're comfortable monitoring live systems and resolving issues in real time.
• A pragmatic approach to software engineering—using just enough code to solve the problem, while keeping complexity in check.

Bonus Skills (Nice to Have)

• Experience with AI/ML technologies or integrating LLMs into applications.
• Knowledge of machine learning for test selection, build optimization, or predictive CI/CD insights.
• Background in using AI to enhance developer tools or automate CI/CD processes.
• Understanding of LLMs and their application in developer workflows.