Senior Software Engineer, Full-Stack

ThreeFlow

About The Position

ThreeFlow is looking for teammates who are naturally curious and love to ask questions, even when it means questioning industry standards. We cultivate an inclusive culture where everyone can contribute, grow, and feel valued. We’re excited to add a Senior Full-Stack Engineer to our Apex team, reporting to the Engineering Manager. As a Senior Software Engineer at ThreeFlow, you’ll make meaningful contributions from early on, working on projects that are important to our success as we scale and move forward post-Series C. Our team collaborates to plan and execute engineering projects to develop and improve client-facing features within our application. Our tech stack uses a Ruby on Rails RESTful API on the back-end with PostgreSQL and Redis, with RSpec for testing and RuboCop for code style. Our UI stack is Vue.js 3 with Vitest for unit testing and ESLint and Prettier for code style. We use Cypress and Playwright for end-to-end testing across the full stack. All of our data and applications are hosted on AWS, with infrastructure managed via CloudFormation. AI is a meaningful and growing part of our product; we use Anthropic Claude models via the Anthropic API and AWS Bedrock for structured data extraction, where recall and accuracy are critical, orchestrated via AWS Step Functions and Lambda. It's deliberate, high-stakes work rather than a bolt-on, and our team is close to it.

Requirements

5+ years of experience building and maintaining highly available web applications, with at least 3 of those years working with Ruby on Rails.
2+ years of recent experience building production UIs with a reactivity-based SPA framework—our stack is Vue.js, and experience with Nuxt or Svelte translates well. React experience is valued, but its reactivity model differs meaningfully from Vue’s; we'll dig into this in the interview, so we encourage you to be specific about your hands-on experience.
Experience with PostgreSQL, with the ability to understand and write efficient queries taking full advantage of Postgres' JSON/B data types.
Meticulous attention to detail and excellent problem-solving, analytical, and troubleshooting skills.
Comfortable using AI tools in your development workflow, with a strong commitment to understanding and owning everything you ship—we encourage AI-assisted development, but not at the expense of code quality or engineering judgment.
Comfortable presenting architectural approaches, recommendations, and decisions to a combination of peers, managers, and non-technical team members, and giving feedback to peers in similar situations.
Experience working with Product Managers to break down specifications for larger efforts into stories, provide order-of-magnitude estimates, and take ownership of efforts through to completion.
Comfortable working on an agile team and enjoy learning new concepts, processes, and technologies.
Strong interest in tying technical solutions to business problems and understanding technology value propositions.

Nice To Haves

Experience working with a component library or design system is preferred.
Familiarity with domain-driven design (DDD) or module-based architecture patterns on the backend is preferred.
Experience working with AWS and Buildkite.
Experience with HIPAA-related data handling.

Responsibilities

Collaborate in an agile environment on a team that includes front-end, back-end, QA, and design specialists.
Partner with product, design, and other specialists to launch new products, iterate on existing features, and build the best user experiences.
Collaborate with the engineering team to build and revise the API that provides the backbone for our three Vue.js-based UIs: Broker, Carrier, and Underwriting.
Build and maintain front-end features across our Vue.js applications, contributing to a shared component library and design system.
Scope new initiatives to determine the work effort and turnaround time.
Write, test, document, and support efficient, reusable code across the full stack.
Participate in design and code reviews.