We at Sigma Software are looking for a Senior Scala Developer to join our fast-growing Mobile & Web Solutions department, uniting over 300 professionals across diverse technologies. You will play a key role in building and evolving a high-load, data-driven social commerce platform used by a global fashion community — a product that blends e-commerce with social interaction, enabling users to buy, sell, and recycle unique fashion items at scale.In this role, you will design and deliver robust Back-End solutions using Scala and JVM technologies, contributing to systems that handle tens of thousands of requests per second. You’ll collaborate closely with an international, UK-based product team, take ownership of major features, and influence technical decisions across scalable architecture, stream processing, data storage, and CI/CD practices.This is a noble opportunity to work in an innovative, knowledge-sharing environment where your expertise directly impacts user experience, search and discovery, platform reliability, and a product that delivers real business and sustainability value.CUSTOMEROur Customer is a UK-based company operating a global fashion marketplace, enabling users to sell customized or rare clothes and accessories. The platform supports sustainable consumption by allowing people to recycle unwanted items for monetary gain. The company has built a strong international presence and is part of the growing social commerce trend, combining e-commerce with community-driven engagement.PROJECTThe project is a social shopping platform blending retail and social networking features. Users create personal profile pages to list items for sale, add images, descriptions, hashtags, and searchable tags. Specializing in clothing and fashion retail, it connects buyers and sellers of unique and second-hand apparel.RESPONSIBILITIESContribute to investigations of new technologies and the design of complex solutionsDevelop well-structured technical solutions and write robust codeCollaborate and communicate professionally with the customer’s teamTake ownership of delivering major solution featuresParticipate in the requirements gathering and clarification processDevelop core modules and platform functionsPerform code reviews, write unit and integration testsREQUIREMENTSAt least 5 years of hands-on experience with ScalaAbility to write high-quality code in TypeScript, Scala, Java, Kotlin, or other JVM languagesProven experience building scalable applications serving tens of thousands of requests per secondSolid experience with relational databases (ideally Postgres)Experience with NoSQL datastores (e.g., DynamoDB)Knowledge of stream processing tools (e.g., Kafka)Understanding of DevOps practices (CI/CD pipelines)Ability to proactively solve complex problems independently and know when to seek guidanceAt least an Upper-Intermediate level of EnglishPERSONAL PROFILEProduct-oriented mindset focused on solving real business problemsPositive thinker with excellent communication skillsAble to initiate new projects and engage new customersPassionate about technology, learning, and sharing knowledgeStrong focus on user experience and product quality