Ingénieur Full Stack/Ingénieure Full Stack

Sanjow is a a european SaaS group specialising in subscription-based digital services across Europe and the UK. Their mission: design robust, optimised, and scalable infrastructures that support rapid growth and foster experimentation.They make life easier for individuals and businesses with turnkey online solutions, particularly in the travel sector — from flight check-ins to airport lounge access, as well as high-volume platforms for ticket purchases. They also operate in other areas such as gift cards and mobile top-ups, while constantly exploring new opportunities, especially in AI.The name Sanjow comes from the combination of the Japanese word for “support” (sanjo) and “flow” — a nod to their DNA of providing smooth, efficient assistance.With headquarters in Paris, an office in Lisbon and colleagues based over the world, Sanjow is a fast-paced international start-up where innovation and collaboration know no borders.The missionTo join their new team of 3 developers building their own payment solution, Sanjow is looking for a highly motivated and talented Full Stack Developer (Node.js).They’re seeking someone with proven expertise — and genuine passion — for the e-commerce sector, hands-on experience in payments and subscriptions, and solid mastery of the Agile SCRUM methodology. This is a small, fast-moving team, so be ready to roll up your sleeves and dive in!You’ll work closely with product leadership and technical peers to design, build, and deploy a modern billing system that includes rebill logic, smart routing, retries, and deep integrations with multiple PSPs.Your main missions will be:Architect and develop Sanjow’s Payment BoxImplement payment features such as smart routing, retry logic, and direct PSP integrationsCollaborate with Product and Data teams to define use cases and KPIsBuild and maintain integrations with existing services and APIsEnsure high availability, traceability, and observability of transactionsHelp define best practices for testing, release cycles, and monitoringTech Stack:Languages: TypeScript / JavaScriptBackend: Node.js, Express, Prisma (NestJS is a plus)Frontend: React, Next.jsDatabase: PostgreSQL, RedisInfrastructure: Render, Vercel, GitHubMethodology: Agile (2-week sprints), CI/CDWhy choose Sanjow?Play a key role in one of their most strategic initiativesEnjoy high autonomy and ownership in a lean, fast-paced environmentBuild critical infrastructure from scratchBenefit from a flexible work culture and flat hierarchyWho they’re looking for:5+ years’ experience as a developer with strong skills in TypeScript, Node.js, and relational databasesProven experience building payment systems, PSPs, or billing logicConfident building API backends and asynchronous workflowsStrong focus on code quality and modular, testable designAutonomous, results-driven, and performance-orientedFluent in English (Portuguese is a strong plus)Bonus points for :Experience with smart retry logic, subscription lifecycles, or multi-MID routingFamiliarity with master gateways such as Rebilly or IxoPayInterest in using AI tools to boost coding and development productivityRecruitment ProcessPhone call with a recruiter from EiquemFirst interview with the CTOTechnical interview with the Tech Lead of the payments teamFinal interview with one of the cofounders