Back End Developer

Backend EngineerPiston Technologies, Inc. — On-site, San Francisco Bay Area (Cupertino, CA)About PistonPiston Technologies is building a closed-loop payment network for the U.S. trucking industry, changing how fleets pay for and manage fuel. Our flagship product, PistonPay, is a cardless fuel payment platform that gives fleets real-time controls, dynamic underwriting, and full visibility at the pump. We integrate directly with fuel retailers' point-of-sale systems to move high volumes of real-time transactions securely and reliably.The RoleWe're looking for an experienced Backend Engineer to design, build, and own the systems behind fuel payments, fleet transactions, loyalty programs, mobile payments, and fuel retail integrations — work that sits squarely at the intersection of B2B and B2C.This role is heavily backend-focused and demands strong experience with Node.js, Express.js, PostgreSQL, distributed systems, and XML-based integrations. The ideal candidate is comfortable owning architecture, leading technical initiatives, and delivering highly scalable production systems.This is a full-time, on-site role in the San Francisco Bay Area.ResponsibilitiesDesign, develop, and maintain backend services using Node.js and Express.jsArchitect and support microservice-based applications and RESTful APIsDesign and optimize PostgreSQL databases for high-volume transactional workloadsBuild and maintain XML-based integrations with third-party platforms and partnersDevelop and support cloud-native applications running in AWSUse Docker, Kubernetes, and CI/CD pipelines to deliver reliable production servicesUphold the security, reliability, and compliance standards expected of a payments platform (e.g., PCI DSS)Collaborate with Product, Operations, and Engineering to deliver scalable solutionsParticipate in architectural planning, technical design reviews, and engineering best practicesRequired Qualifications5+ years of software engineering experienceStrong experience with:Node.jsExpress.jsPostgreSQLRESTful API designMicroservice architecturesRedisXML-based integrationsExperience designing and operating highly available, transaction-oriented systemsExperience with AWSExperience with Docker, Kubernetes, and CI/CD processesStrong understanding of distributed systems, scalability, performance optimization, and database architecturePreferred QualificationsExperience with one or more of the following:Conexxus standards and XML messaging specificationsConexxus Mobile Payments, EPS, or Site Systems implementationsVerifone Commander and Verifone forecourt integrationsGilbarco Passport and forecourt controller integrationsNACS standards and fuel retail operational workflowsFuel payment processing, loyalty platforms, fleet card systems, or forecourt technologiesPayment authorization, settlement, and reconciliation systemsIdeal CandidateYou're a highly experienced backend engineer who enjoys solving complex integration challenges across B2B and B2C architectures. You have a strong foundation in modern backend development and understand how large-scale transactional systems behave in production. Experience in fuel retail, payments, or convenience retail technology is highly valued.