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.RESPONSIBILITIES Contribute to investigations of new technologies and the design of complex solutions Develop well-structured technical solutions and write robust code Collaborate and communicate professionally with the customer’s team Take ownership of delivering major solution features Participate in the requirements gathering and clarification process Develop core modules and platform functions Perform code reviews, write unit and integration tests REQUIREMENTS At least 5 years of hands-on experience with Scala Ability to write high-quality code in TypeScript, Scala, Java, Kotlin, or other JVM languages Proven experience building scalable applications serving tens of thousands of requests per second Solid 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 guidance At least an Upper-Intermediate level of English PERSONAL PROFILE Product-oriented mindset focused on solving real business problems Positive thinker with excellent communication skills Able to initiate new projects and engage new customers Passionate about technology, learning, and sharing knowledge Strong focus on user experience and product quality