--- title: 'Senior JavaScript Engineer (Full-stack, Retention) at Relay Commerce' canonical: 'https://feeny.ai/job/senior-javascript-engineer-full-stack-retention-relay-commerce-lisbon-8fmbqeyqj3q7' type: 'job' last_seen: '2026-09-18' --- # Senior JavaScript Engineer (Full-stack, Retention) at Relay Commerce - **Company:** Relay Commerce - **Location:** Lisbon, Portugal - **Employment:** full-time - **Work type:** remote - **Posted:** 2026-09-14 - **Last confirmed live:** 2026-09-18 - **Apply:** https://jobs.lever.co/relay-commerce/bb23179a-f4e5-4cc0-b4f6-d05c18765c90 ## Job description ## 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. Primary Responsibilities - Work as part of a skilled, AI-native, multi-disciplined product engineering team to rapidly deliver modern software, to excellent quality standards, across high-volume subscription and billing systems. - Design and deliver serverless TypeScript services on AWS Lambda, backed by MySQL and Prisma ORM. - Contribute to efficient, modern React applications which rely on our APIs and integrate with the Shopify and Klaviyo ecosystems. - Own features end-to-end, working with your team to make sure we ship solutions to real customer problems. - Support our Customer Success team by joining our working hours escalation schedule, operating and maintaining the live production system. - Participate in architectural discussions and technical decision making across Relo and the rest of Relay Commerce. - Add agent context to codebases, run coding agents, build MCPs and AI product features to open our platform to LLMs such as Shopify’s Sidekick. - Contribute improvements to processes, guidelines, and documentation in a fully-remote organisation. Important Traits for Success - You are comfortable taking loosely defined product ideas and turning them into concrete technical solutions. - You effectively use AI agents such as Claude code or Codex to deliver working, reliable software at pace. You understand and can explain skills, MCP’s, RAG and other aspects of AI tooling. You know when to delegate to Claude and Codex, and when not to. - You communicate clearly in writing. Design proposals, pull requests, and technical discussions should be concise and easy for other engineers to follow. - You consider the operational impact of the systems you build. You think about reliability, observability, security, and performance before and during development. - You are comfortable working across the stack when needed; front-end with React, back-end with REST APIs and CLI scripts, in the database, with infrastructure-as-code, or with cloud-native services. - You take accountability for the systems you build and follow issues through to resolution with a high degree of quality control. Required Expertise We are looking for someone who can comfortably describe themselves as a Senior JavaScript Engineer (with significant experience using JS and TS full-stack), who is experienced in owning features from idea to delivery. Technical - Significant, proven, senior-level experience with JavaScript across multiple frameworks. Our guidance is a minimum of 8 years across multiple companies. - Extensive experience designing REST APIs, especially for systems that integrate with third-party platforms. - Deep expertise crafting TypeScript using class-oriented design, strong typing, SOLID principles, OOP patterns, and test-driven development. - Strong SQL and relational database knowledge; understanding of query performance, indexing strategies, and schema design in MySQL or another RDBMS. - Clear proficiency with React; able to implement components, build interactive UI, manage application state, and integrate cleanly with backend APIs. - Experience with cloud-native services in Amazon Web Services. - Highly desirable: Experience with predictive algorithms - Highly desirable: Experience with the Shopify platform, structures, and data - Highly desirable: Experience with SRE practices and observability tools like DataDog. Product - Delivery experience; you have defined and shipped major features as part of a team. - Excellent written and verbal communication skills; you can deliver clear and succinct explanations of technical topics for a variety of audiences. - Customer focus; you put customers, their needs, and their experience first. The interview process: - Initial call (30 minutes). You’ll speak with our Engineering Manager for Relo, Joel Jenvey, discussing your approach to problem solving, engineering expertise, knowledge of JavaScript, and use of LLMs. - Second round (1 hour 30 minutes) - You’ll meet with our Engineering Manager, Joel Jenvey again, and a colleague from the current Relo development team. We would like you to demonstrate your senior level of technical experience. We ask all hands-on team members to complete a refactoring exercise for 30mins with the interviewers. We’ll discuss your technical assessment, and then move on to more specific questions about your skills and experience in technical areas. - Final round (45 minutes) - You’ll meet with our CTO, Tom Russell, and our GM for Retention, Gauthier Derrien. They’ll be particularly interested in how you collaborate with non-engineering team members. ## Benefits & Perks - Flexible Time Off - Public Holidays Off - Paid Parental Leave - Work From Home Stipend - Therapy/Mental Health Reimbursement - Co-working Space Allowance - Company Swag Relay Commerce is an equal opportunity employer. We celebrate diversity and are committed to creating an inclusive environment for all team members. ## About Relay Commerce ## Company Overview - **One-liner**: Relay Commerce enables e-commerce merchant success by acquiring, operating, and scaling a suite of SaaS tools for SMBs to attract, convert, and retain customers. - **Entity Type**: Private (Series Seed) - **Headquarters**: New York, New York, United States - **Founded**: 2021 - **Founders**: Austin Simon (CEO) ## Core Business - **Primary industries**: E-commerce enablement, SaaS, Software Development - **Target customers**: Small and medium-sized (SMB) e-commerce businesses, primarily on Shopify and Amazon - **Mission or purpose statement**: "We enable merchant success" by providing enterprise-grade scaling solutions. ## Products & Services Relay operates and grows a suite of acquired e-commerce SaaS products: - **SmartrMail**: AI-powered email and SMS marketing solution for SMB e-commerce merchants. - **Peel Insights**: Retention analytics solution for Shopify and Amazon brands, providing customer insights and subscription management. - **Fomo**: A social proof notification tool to increase conversions. Acquired in 2022. - **Relo**: An e-commerce tool (details less public). - **SavedBy**: Package protection service that protects against loss, theft, and damage. - **Personalized Messaging**: A module for targeted, one-to-one customer communication. ## Market Standing - **Valuation/Market Cap**: Not publicly available (Private company). - **Key Metric**: Total Funding of **$27M** across 3 rounds (Pre-Seed, Seed, Debt Financing). - **Notable Investors/Partners**: **Primary Venture Partners** (Led Seed and Pre-Seed), **TriplePoint Capital** (Led Debt Financing). - **Growth Signals**: Drives over **$1 billion** in aggregate incremental Gross Merchandise Volume for **35,000+ merchants**. Has acquired four companies (Fomo, Relo, SmartrMail, Peel Insights) in a buy-and-build strategy. Strong global presence with team members in 15+ countries. ## Competitive Advantages - **Buy-and-Build Model**: Relay acquires established niche e-commerce SaaS tools and accelerates their growth using a central operating team, rather than building from scratch. This allows for rapid portfolio expansion and shared resources. - **Integrated Suite**: Instead of offering standalone point solutions, Relay aims to provide a complete revenue engine (attract, convert, retain) that integrates across its products. - **Partner Approach**: Positions itself as a "dedicated revenue partner" that works alongside in-house or agency teams to optimize tools for results, differentiating from companies that just sell software. ## Strategic Focus - **Post-Acquisition Growth**: The core strategy is to acquire exceptional e-commerce SaaS companies and pair them with a world-class operating team to accelerate growth and scale. - **Product Integration**: Unifying the acquired tools (SmartrMail, Fomo, Peel, etc.) into a seamless, comprehensive suite for merchants. - **Global Talent Expansion**: Actively hiring across multiple countries (Brazil, Portugal, US) to build a distributed, world-class team. ## Why Work Here - **Culture & Values**: Describes a "master-apprentice" leadership model where leaders aim to instill parts of themselves in those they lead. Emphasizes professional development, providing challenges for team members to learn and grow. - **Remote-First & Global**: The team is globally distributed across 15+ countries, with a strong emphasis on asynchronous communication. The Staff Engineer quoted says this is "the better way to work and be productive." - **Benefits**: Includes a work from home stipend, health & wellness perks, paid parental leave, company holiday bonus, incentive compensation & bonuses, professional development, unlimited PTO, and company & team travel (monthly team building & annual retreats). - **Growth Stage**: As a well-funded, growing company (80+ team members) that has just made key acquisitions, there is opportunity for significant impact and career growth. ## Sources 1. [relaycommerce.io](https://www.relaycommerce.io/) 2. [relaycommerce.io/careers](https://www.relaycommerce.io/careers) 3. [relaycommerce.io/about-us](https://relaycommerce.io/about-us) 4. [linkedin.com/company/relay-commerce](https://linkedin.com/company/relay-commerce) 5. [jobs.lever.co/relay-commerce](https://jobs.lever.co/relay-commerce) ## Other roles at Relay Commerce - [Manager, Customer Success](https://feeny.ai/job/manager-customer-success-relay-commerce-florianopolis-sswrs42a4s0b) — Florianópolis, Brazil - [Finance & Accounting Analyst](https://feeny.ai/job/finance-accounting-analyst-relay-commerce-florianopolis-97wf94p8ptme) — Florianópolis, Brazil