Staff Software Engineer

This is a small, high-autonomy team — you'll work directly with the Product Manager and your engineering peers, and you'll be trusted to take an ambiguous problem and figure out the right shape of the solution. That extends past your own surfaces: we want someone who thinks in systems, flags it when we're about to duplicate work that already exists elsewhere, and pushes back on how something's built when there's a better way to do it.

Responsibilities

• —Own Shopify checkout and post-purchase features. Build and maintain the extensions that render Rebuy offers inside Shopify's checkout, thank-you, customer-account, and post-purchase surfaces, and the server-side code that decides what they show. Understand and work within the limits Shopify imposes on these runtimes: bundle size, sandboxed APIs, and strict review.

• —Rebuild experimentation reporting. Smart Flows and A/B Testing need their reporting rebuilt so merchants can see what an experiment actually did. You'll design the data model, the PHP and TypeScript endpoints, and the BigQuery and MySQL queries behind it, and make sure the numbers are right.

• —Build robust REST APIs. Design and implement secure, well-structured REST APIs in PHP and TypeScript that serve our extensions, admin, and Shopify integrations. Rebuy's own services are REST; GraphQL is how we talk to Shopify.

• —Keep production healthy. Investigate merchant-reported problems that come to the team through our Product Manager, find the root cause, fix it, and improve logging and metrics so the next one is caught before a merchant reports it. This includes rotating on-call.

• —Work AI-first. We use Anthropic's Claude Code across development, review, and testing. You'll be expected to be fluent in that way of working, to know what you can accomplish with it, and to be clear about where your own judgment is the thing that matters.

• —Do your own quality assurance. There is no hand-off to a QA team. You test what you build, in unit and end-to-end suites and by hand against real Shopify stores, and you don't call it done until it works the way it should.

• —Look beyond your own ticket. Review code and weigh in on technical decisions outside your immediate surfaces, mentor by example rather than title, and route ad hoc requests that land in your DMs back through the Product Manager so they get prioritized properly.

The Hard Skills

• —Proven track record operating with Staff-level ownership: minimal spec, driving a technical decision or migration end-to-end across multiple systems or teams, influencing engineering decisions outside your own team.

• —Fluent daily use of AI coding tools, with the judgment to tell a plausible-looking result from a correct one. You can explain what you accomplish with them and where your own value comes in.

• —Strong troubleshooting in an unfamiliar codebase. You can read a stack trace or a failing test back to its cause, in TypeScript or PHP, without someone walking you through the system first.

• —8+ years building production web applications, with hands-on experience shipping and maintaining both PHP (CodeIgniter 4 or a comparable MVC framework) and TypeScript with React.

• —Experience owning a revenue-critical, customer-facing system in production: reading logs and metrics, triaging escalations, and following incidents through to a fix.

• —Hands-on experience with BigQuery on Google Cloud or another columnar warehouse, including writing analytical queries and being aware of their cost, plus comfort with MySQL schema design and migrations.

• —Testing discipline across unit and end-to-end suites, and the habit of doing your own QA rather than handing it off.

• —Solid understanding of secure coding fundamentals for systems that handle buyer and order data, including the OWASP Top 10 — this touches payment flows and customer data, so sound judgment here matters.

• —A track record with orchestration and building platform-wide, componentized systems.

• —A strong fit for remote-first, high-autonomy culture: fast, present, and responsive on Slack during working hours.

• —Educational background in CS / Engineering or a similar area, or equivalent experience.

Preferred

• —Shopify app development, especially Checkout Extensibility, post-purchase extensions, or the Admin and Storefront GraphQL APIs. Experience in another tightly constrained runtime, such as React Native, translates well.

• —Preact

• —Comfortable moving between Kanban and Sprint-based workflows.