Senior Full Stack Engineer

Senior Full Stack EngineerSincere is looking for a Senior Full Stack Engineer to help us make our products meaningfully better. This is a high-ownership individual contributor role for a seasoned engineer who can take a broad product area, understand the customer and business needs, and ship high-quality improvements.You will:Build full-stack features across Ruby on Rails and Next.jsOwn product initiatives end-to-end, from identifying opportunities and shaping solutions through implementation, launch, and iterationPartner with product/project managers and designers to identify customer pain points, uncover product opportunities, and deliver meaningful improvementsUse tools like Claude Code and Codex as a core part of your workflow to explore, develop, test, and shipMake practical technical decisions that balance speed, quality, maintainability, performance, and customer impactBuild polished, reliable, easy-to-use experiences with strong attention to UXUse tools like Datadog and Mixpanel to monitor production behavior, investigate issues, and inform product decisionsChampion new ideas and continuously look for ways to improve our products, engineering practices, and customer experienceYou are:A seasoned full-stack engineer with 7+ years of professional software development experienceComfortable working across our stack, including Ruby on Rails, TypeScript, React, Next.js, MySQL/Postgres, Redis, MongoDB, Sidekiq, OpenSearch, AWS, and DockerFluent with AI-assisted development tools such as Claude Code or CodexProven at building and maintaining large-scale customer-facing web applicationsProduct-minded, with strong instincts for customer needs, UX quality, business value, and technical tradeoffsA self-starter who brings structure to loosely defined problems and drives them through executionA strong partner to DevOps, with enough understanding of system architecture, cloud infrastructure (AWS), deployment, containerization, and infrastructure-as-code (Terraform) to collaborate effectivelySkilled at working in mature codebases, understanding existing architecture, and improving systems pragmaticallyDetail-oriented, with high standards for both the code and the customer experienceEntrepreneurial, curious, and biased toward building, experimenting, and shippingCollaborative and low-ego, with strong communication skills and pride in your craft