Backend Engineer, UI Platform

Description

The company is a financial infrastructure platform for businesses. Millions of companies, from large enterprises to early-stage startups, use it to take payments and grow revenue.

The UI Platform team, called Sail, builds the foundations behind the Dashboard and other user interfaces. Sail Services owns the systems that evaluate feature flags and experiments, ingest frontend analytics, and speed up Dashboard load times for the largest merchants.

The team builds backend-for-frontend capabilities that connect the company's backend systems to its UI platform, so product teams can build and run user experiences without rebuilding the same infrastructure each time.

Responsibilities

• Help build and evolve the systems that power the company's user interfaces, from APIs and GraphQL integrations to edge systems, architectural migrations, and the tooling needed to run them safely at scale.
• Own software projects end to end: agree on priorities, scope the problem on your own, then carry the solution through design, implementation, testing, rollout, and operation.
• Design, build, and run reliable, scalable APIs and backend systems for the Dashboard, mobile apps, and other user interfaces.
• Modernize the UI architecture through incremental migrations, automated validation, shadow traffic, and tightly controlled production rollouts.
• Improve reliability, observability, performance, and operability of services on critical user paths.
• Work with frontend, backend, and infrastructure engineers to understand their needs, and turn recurring problems into reusable platform capabilities.
• Use AI-assisted and agentic development workflows to speed up implementation, testing, validation, and delivery.
• Review code, join technical discussions, and write documentation and runbooks that raise the quality of the team's work.

Requirements

• Fluency with AI-assisted and agentic development tools in daily engineering work, including critically reviewing, validating, and improving the code they generate.
• 2+ years of professional software engineering experience, or equivalent practical experience, building, shipping, and operating production systems.
• Solid backend and infrastructure knowledge: APIs, data storage, distributed systems, and production operations.
• Able to scope and deliver open-ended software projects on your own, making practical technical and product trade-offs with limited oversight.
• Strong debugging and problem-solving skills, with attention to testing, maintainability, reliability, and user impact.
• Clear written and verbal communication, and the ability to work well with frontend engineers, product engineers, and infrastructure partners.
• Preferred, not required: experience building backend-for-frontend systems, UI platform services, developer platforms, or shared infrastructure.
• Preferred, not required: experience designing or integrating APIs, including GraphQL APIs.
• Preferred, not required: experience with high-throughput event ingestion, feature flag or experimentation systems, or other latency-sensitive platform services.
• Preferred, not required: familiarity with caching, asynchronous systems, configuration systems, or data-consistency trade-offs.
• Preferred, not required: experience running large migrations using automated validation, shadow traffic, feature flags, or staged rollouts.
• Preferred, not required: experience using data, developer feedback, or operational signals to improve a platform or developer-facing product.