Senior JavaScript Engineer (Full-stack, Retention) em Portugal

About the Company Relay Commerce is an e-commerce enablement platform offering scaling solutions across personalized messaging, social commerce, and customer retention, helping merchants navigate the rapidly evolving digital landscape with a comprehensive suite of tools. The Relay suite of solutions currently drives more than $1 billion in aggregate incremental gross merchandise volume for more than 35,000 merchants. The Relay ecosystem currently consists of seven software products that accelerate merchant revenue growth through email marketing automation, on-page conversion optimization, user generated content management, retention analytics, and subscription management. Relay’s suite of products are established as key revenue generation tools for innovative e-commerce merchants worldwide. About the Role This is a primarily back-end role (~70%) where you will design and evolve TypeScript services that power personalized replenishment, cross-sell, and subscription offers used by Shopify stores processing millions of transactions. You will own features end-to-end, shaping the problem with a Senior Product Manager, proposing the architecture, implementing the solution with the support of AI, and monitoring and operating it in production.

These systems need to be reliable, observable, maintainable, and performant. You will effectively use AI agents such as Claude code and Codex to deliver at pace. You will also contribute to our React-based front-ends (~30%) when delivering features as part of an experienced multi-functional team. About the Product Relo, a Relay company, helps consumer goods and subscription brands unlock more than 30% additional revenue from their existing customers. The platform gets one-time buyers to order again, turns more customers into subscribers, and keeps them loyal. It does this through an engine that predicts when each customer is ready to reorder, making recurring revenue easy for scaling Shopify merchants.