• Design and build scalable backend systems, APIs, and data pipelines • Own services end-to-end, including architecture, development, deployment, and operation • Lead technical design discussions and contribute to system architecture decisions • Write high-quality, maintainable code and drive engineering best practices • Debug complex production issues and implement long-term, scalable solutions • Improve system performance, reliability, and observability across the platform • Partner closely with Product, Data, and other Engineering teams to deliver impactful features • Mentor junior engineers and contribute to a strong engineering culture • Participate in incident response and on-call rotations

• At the Innovation Lab, we are looking for a developer with strong software development experience who is passionate about hands-on experimentation and has a curious eye for new technologies, especially Artificial Intelligence (AI) and Large Language Models (LLMs). • As a Business Innovation Developer, you will be responsible for developing proofs of concept (PoCs), exploring the technical and market viability of new AI-based applications. • In our Lab, we experiment quickly: short cycles, constant testing with real users, and a focus on converting good ideas into business opportunities.

• Build and scale end-to-end production systems for a complex B2B product • Own features from conception through launch and iteration • Work directly with stakeholders to understand problems and drive solutions • Build shared abstractions and experiences that make complex products intuitive • Raise the engineering bar through excellent code, thoughtful reviews, and clear communication

• Ship full-stack AI projects end-to-end on a product built in Ruby on Rails backend and React frontend. • Design and run experiments (including A/B tests, AI evaluations, or others) to validate AI features, measure impact, and guide iteration. • Build and integrate components for AI infrastructure and optimize them for performance and reliability to support production-level inferencing. • Improve processes, tools, and systems to scale AI features into production-ready solutions. • Help us stay up-to-date with the cutting-edge AI research, techniques, and tools. • Work closely with Circle's leaders and designers throughout the feature design process. • Foster a bias for action by prioritizing speed of iteration, experimentation, and learning, while maintaining high standards of code quality and user experience.