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 noanycreep)

• 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.