Selleo

Selleo is a Poland-based custom software development company founded in 2005, specializing in building web and mobile applications for startups and enterprises alike. With a team of over 100 developers, designers, and tech leads, the company focuses on delivering end-to-end product development services, from initial discovery and MVP creation to full-scale platform development and ongoing support. Their particular expertise lies in EdTech, HRTech, and SaaS solutions, where they have built a strong portfolio of learning management systems, talent management platforms, and business training software. The company positions itself as a product-minded development partner rather than a traditional outsourcing vendor, emphasizing strategic thinking alongside technical execution. Selleo offers dedicated development teams, staff augmentation, rapid prototyping, and AI integration services, with a technology stack centered on React, Node.js (NestJS), React Native, Ruby on Rails, Ember, and Python. Their client-centric approach includes transparent communication, weekly demos, and a notable risk-free trial offering two weeks of developer testing at no cost. Recognized with Forbes Diamonds 2025 for business excellence and maintaining a 4.5 rating on Clutch, Selleo has established long-term partnerships with clients averaging multiple years of collaboration. The company maintains certifications in software testing, cloud architecture, and Scrum methodologies, reflecting their commitment to engineering quality and agile delivery practices.