Senior Software Engineer, Agentic Harness Quality and Performance

Good Systems is the parent company behind Goodnotes, where millions of people capture and develop their ideas. Goodnotes is where we started, and it’s now the foundation for a growing family of products. By reimagining how we interact with information, we’re bringing together human creativity and the breakthrough capabilities of AI. We build products that help people turn good thinking into good work. Our Values Dream big - Be visionary, strategic, and open to innovation Build great things - Work in service of our users, always improving and pushing higher Operate like an owner - Take responsibility with bold decision-making and bias for action Win like a sports team - Be trusting and collaborative while empowering others Learn and grow fast - Never stop learning and iterate fast Share our passion - Share ideas and practice enthusiasm and joy Be user obsessed - Empathetic, inquisitive, practical About the role You join Paddington, our AI-native product line inside Goodnotes, and work directly with Steven, our founder, and a small team shipping new products. Engineers own the full cycle: they design, build, test, ship, and operate what they ship. Coding agents write the code, and the engineer who merges it owns what lands. You set up our quality practice. You build the agentic harness, the guides and automated checks around those agents, and you teach engineers to extend it. You are a software engineer who cares about quality. You lead the quality domain across the squads as an individual contributor and report to the Engineering Manager. We hire at Senior level and welcome Staff-level candidates. - This role will be required to work on-site, 5 days per week in our London Paddington office - This is a permanent role - This role does not include visa sponsorship This is the role for you if you're excited to work on: - Product first: Start in a product squad on day one. Ship with the team and learn how we design, build, and release, as its customer. Then build the quality practice, and keep 20 to 30 percent of your time in a squad. - Harness design: Design the guides and automated checks that steer coding agents before they act and correct them after. Track which checks fire and which never fire. Squads choose what to adopt, so make it worth the choice. - Fast feedback: Put fast, deterministic checks in the agent session and at pre-commit, and slow checks in CI. Write every check's message so the agent can fix the problem itself. - Defect discovery and risk gates: Study past defect classes and design protection against each. Partner with squads on how we find defects before release, including AI-native approaches. Add a gate only where risk needs one, for example LLM review of risky pull requests. Report escaped defects per release and drive them down. - Every platform we build for: We build for iOS, Android, Mac, Windows, web, and backend. You support all of them. Package guides and checks per platform, so new repos start protected. - Engineer enablement: Teach engineers to build and tune their own checks, so the practice spreads through the squads. The skills you will need to be successful: - 5 or more years in software or quality engineering, including quality frameworks, platforms, or harnesses for a team that ships through coding agents. You build agentic workflows yourself, beyond chat. - Static analysis in depth: custom lint rules, dependency rules, and messages that guide a fix. You design pre-commit and CI flows, with fast checks early and slow checks after integration. - You code in at least one of Swift, TypeScript, Rust, Go, or Java, and you write scripts and small systems fast. - You make teams self-serve. Others adopt and extend your tools. - You judge "good enough". You keep rules and feedback from overwhelming the team or the agents. - You work with engineers, designers, and product. You set your own agenda, act before you are asked, and handle ambiguity and conflict. Preferred: - You built LLM-as-judge checks or eval suites for AI product output. - You wrote architecture fitness functions for performance, security, or observability. - You know web, desktop, or mobile test tools, iOS and Android in particular. - You worked on a full-cycle team and operated what you built. The interview process: - Talent Intro Call: A conversation with our Talent Acquisition team to dive into your experience, what motivates you, and why you're interested in joining Goodnotes. - Technical Pre-screen: A short Software Engineering-focused online rapid-fire questions round. - Role-Specific Assessment: A live session in our London Paddington office, focused on the core technical skills for this role. You use your own coding agent on a hands-on exercise, then talk through how you would design the harness. This is your chance to show us how you tackle real-world challenges. - Hiring Manager Interview: A deeper dive into your professional background, your preferred ways of working, and the specific impact you'll have within the team. - Values-Based Panel Interview: A conversation with 2-3 team members centred on our company values. We'll discuss past experiences to see how your approach aligns with our culture. - AI Literacy: As an AI-first company, we'll meet with one of our AI champions to discuss your curiosity, understanding, and practical use of AI tools in your daily workflow. What's in it for you: - Customized Growth & Wellness Budgets: We provide dedicated stipends for the things that keep you at your best, including noise-cancelling headphones for deep focus, professional training, personal development, and health and wellness activities. - Global Connectivity: While we embrace flexible work, we love seeing each other. We provide sponsored visits to our beautiful office locations to foster face-to-face collaboration. - Company-Wide Offsites: Once a year, we gather the entire global team in person to celebrate our wins, align on our vision, and build lasting connections. - Comprehensive Health Coverage: Your well-being is our priority. We offer premium medical insurance for you and a dependent to ensure peace of mind for you and your family. - 24 remote working days per year: Giving you the freedom to work from a location that suits your life. Whether that's closer to family, while travelling, or simply a change of scenery to refresh your focus. Goodnotes is committed to fostering a diverse, inclusive, and equitable workplace. We welcome applications from individuals of all backgrounds, identities, and experiences, making all employment decisions based strictly on merit, qualifications, and business needs. Note: Employment is contingent upon successful completion of background checks, including verification of employment, education, and criminal records. By submitting your application, you acknowledge that you have read and understood our Candidate Privacy Notice, which provides important information about the data we collect during the application process. You can find it here.