Software Engineer (Full-Stack) - Core/Web Team

Software Engineer (Full-Stack) - Core/Web Team Role Overview Join Fonn’s Core/Web team and help develop our construction project management SaaS platform, already trusted by over 100,000 users . You’ll work across our React frontend and Node.js backend—building user-facing features as well as core platform capabilities that power the entire Fonn ecosystem. What will you be working with? Frontend Modern React 18 application (TypeScript, hooks) TanStack Query and MobX for state management Webpack 5 setup with SWC compiler SCSS modules with linting and style guides Jest + React Testing Library for frontend testing GitLab pipelines and CI/CD workflows Backend Node.js with Express.js and NestJS MSSQL databases with Sequelize ORM RESTful APIs Testing frameworks for backend (Jest, Mocha, Chai, Supertest) Requirements 4+ years full stack development experience Solid understanding of JavaScript runtime fundamentals (event loop, microtasks / macrotasks) Knowledge of how the browser rendering pipeline works (DOM parsing, style calculation, layout, paint, compositing) and how code impacts performance Understanding of React's reconciliation process (virtual DOM diffing, rendering phases, batching, concurrent rendering in React 18) Strong knowledge of TypeScript (generics, strict types and no any creep) Knowledge of SCSS preprocessor and modern CSS features (Grid, Flexbox) Comfortable working with CI/CD pipelines (GitLab jobs, caching, deployment scripts) Familiarity with performance profiling (React Profiler, Lighthouse, bundle analysis) and applying optimizations Experience in writing and maintaining unit and integration tests (Jest, RTL, Mocha/Chai) Understanding NestJS fundamentals (routing, middleware, dependency injection, modular architecture) Experience with SQL databases and ORMs (Sequelize) Familiarity with designing and maintaining RESTful APIs Excellent communication skills in both English and Polish. Nice to have Expierience with using AI assisted development tooling Expierience with publishing and leveraging MCP servers Familiarity with Storybook for component development Familiarity with SignalR Familiarity with Formik for forms Familiarity with Bootstrap 4/5) Familiarity with document viewers (PDFTron) and 3D visualization (Xeokit / WebGL). Familiarity with developing and maintaing distributed microservices application on Azure PaaS infrastructure Familiarity with event-driven architectures and message queues Familiarity with Docker and containerization Previous work with SaaS platforms at scale Understanding of OAuth/OIDC authentication flows Experience with construction, project management, or document management software Key Responsibilities Full stack product development : Build end-to-end features spanning React frontend through Node.js backend services and SQL/CosmosDB databases. Actively participate in product engineering process : Take ownership of features throughout their lifecycle, help refine requirmenets and contribute to agile processes Write Clean Code : Write maintainable, easily readable code following patterns and conventions adopted amongst the team Quality focus : Implement comprehensive unit and integration tests Performance : Optimize both frontend UX and backend API performance for our growing user base Code Reviews : Participate actively in code reviews, provide feedback unlocking further improvements What We Offer Technical Growth : Work on challenging integration projects including upcoming Access Evo platform integration Spearhead of Engineering Efficiency : Use best available AI supported tooling Architecture Influence : Shape the evolution of our microservices architecture and frontend ecosystem Scale Impact : Your code will serve tens of thousands of construction professionals daily Industry Impact : Build software that streamlines construction project management for teams worldwide Mentorship : Work alongside experienced engineers in a collaborative, learning-focused environment Who we are? Fonn is a construction project management SaaS platform, founded in Norway in 2016 to digitalize and simplify the way contractors work. Our software helps construction professionals streamline communication, improve collaboration, reduce costs, and keep projects on schedule. Today, more than 100,000 users worldwide rely on Fonn to manage their projects more efficiently. Since joining The Access Group —one of the UK’s leading providers of business management software, supporting over 160,000 organizations globally—we’ve gained the scale and resources to accelerate our mission. As part of Access, we remain committed to delivering innovative solutions tailored to the construction industry, while also contributing to the wider Access ecosystem of integrated SaaS products. With our engineering headquarters in Wrocław, Poland, we’re building reliable, scalable technology that empowers construction teams daily—and shaping the future of construction tech within the broader Access family. Apply! Sparked your interest? Please apply now and get more information and talk to our specialists. Note: Thank you for your interest in joining our team. We truly appreciate the time and effort you’ve taken to apply. Please be advised that we will be moving forward with only the candidates selected for the next stage of the process. If you are chosen, you will hear from us directly. Please kindly note that this is a hybrid position! Please kindly remember to add to your resume the below consent: „I agree to the processing of personal data provided in this document for realising the recruitment process pursuant to the Personal Data Protection Act of 10 May 2018 (Journal of Laws 2018, item 1000) and in agreement with Regulation (EU) 2016/679 of the European Parliament and of the Council of 27 April 2016 on the protection of natural persons with regard to the processing of personal data and on the free movement of such data, and repealing Directive 95/46/EC (General Data Protection Regulation)”. If you like you may add: „I also consent to the processing of my personal data for the purposes of any future recruitment processes.” Link to our Personal Data Privacy Notice for Candidates: https://fonn.com/privacy-policy-for-candidates