Software Engineer, Backend Developer, Javascript

At Rebuy, we’re on a mission to revolutionize shopping with intelligent, personalized experiences that wow customers around the globe. As a fully remote team, we power some of the fastest-growing DTC brands like Tecovas, Momofuku, Dime Beauty, Liquid Death, Magic Spoon, OLLY, and many more.

We believe in ownership, drive, and empathy, and strongly uphold that every team member plays a vital role in shaping the future of intelligent commerce. Our culture thrives on collaboration, creativity, and genuine passion. We don’t just build great tech - we build lasting partnerships, a strong community, and a place where people love to work.

You’ll join the team that owns Checkout, Post-Purchase, Smart Flows, and A/B Testing — what a shopper sees during and after checkout on Shopify, and the tools merchants use to run experiments on their stores. Some of these surfaces run inside Shopify's checkout and post-purchase pages, some of the most constrained runtimes in web development; others are our own PHP services, a Type Script API, MySQL, and a Big Query event pipeline.

You’ll work across all of it. Some days it means a rendering bug in a checkout extension; other days it means an experiment reporting query, a PHP endpoint, or a schema migration that has to come back fast and cheap.

We work AI‑first, and we expect you to already know how to get real work out of AI coding tools and how to tell when they are wrong.

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.

• 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 Type Script endpoints, and the Big Query 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 Type Script 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…