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Full Stack Engineer



Software Engineering
Zagreb, Croatia
Posted on Wednesday, June 26, 2024

At Fonoa, we are transforming how digital-first companies stay tax compliant. We provide simple and modular API solutions that easily integrate into any existing workflow. Through our technology first approach, we reduce manual processes, increase compliance and reduce the cost of operations when transacting and scaling internationally.

We are solving one of the largest yet unsolved problems in global e-commerce. Our tax automation software enables companies such as Uber, Zoom,, Squarespace and Rappi to expand their international offerings more quickly and stay tax compliant.

Engineering plays a very central part in the business.

As a company with ambitions to be a world-class API solution for all things tax, we value quality over quantity when building, and we care about creating scalable and maintainable software that our customers and daily users can rely on.

Some pointers about our engineering culture:

  • Engineers are given customer problems to solve rather than features to build.
  • We understand the customer's needs before considering implementation details.
  • Engineers are owners of their past, present and future; architecture, tools, coding, testing, deployment, operations and scaling
  • We work in lean, small teams. We co-own the product roadmap with product managers
  • We choose collaboration, compassion and trust over individualism and politics
  • We prefer innovation, constant iteration and trust over competition and perfect solutions.
  • We support each other, are kind by nature, and give as much feedback to improve as professionals.
  • We break down complex problems and consistently seek to find the most straightforward solutions.
  • We take quality seriously and factor it into everything we do.
  • We are comfortable with change, either in priorities, goals and deadlines. We see this more as an opportunity than a hurdle. We are not satisfied with the status quo and push for change.
  • We seek those looking to make a severe impact and are excited about working in a high-growth startup.
  • We ship fast, continuously, and iteratively, learning each step.
  • We are data-informed. And are ok with finding the data when it’s missing.

Our products

We have a suite of API products that automate tax-related workflows for any internet company. Those products are Lookup, Tax, Returns, Data sharing and E-Invoicing.

We may discover novel customer needs as we learn and spin up new products as required.

Our API docs

For you as an engineer, API documentation is probably an important part when considering a new career move. Thanks to the API docs, you can recognise how API works and how it is structured.

Please, visit our API documentation and learn more about our API endpoints and how to use them -

Our Tech Stack

Fonoa has a suite of API products that automate tax-related workflows for any internet company. Check them out below:

  • For backend, we use Node and Go
  • For the frontend, we use ReactJS and Typescript
  • For persistence, we use PostgreSQL
  • We use Azure and GCP for our cloud services
  • We manage our infrastructure with Terraform, Kubernetes CRDs, ArgoCD and DataDog.

“As an engineer, I follow a product through its lifecycle, from ideation to delivery and support, which gives a lot of exposure to the technology and customer needs. This allows me to learn to improve both myself and the product constantly.” - Philip Beel, Engineering Manager.

What you will do

  • Learn about how painful it is for companies to handle tax manually, and think about how our products are changing the status quo
  • Own what you build, with the ability to decide how to make it and the responsibility of operating it in the production environment.
  • Build meaningful products with REST APIs that our customers use and depend on for everyday business (finance, operation, tax and developer teams)
  • Build new product features across the stack, from back-end business logic implementation to front-end customer-facing interfaces.
  • Write high quality robust, modular code for frontend and backend
  • Ensure the technical feasibility of UI/UX designs as well as internal applications capabilities
  • Record and collate lots and lots of data sets from all these operations for long-term storage and future insight
  • Use every learning and observation to improve our products, constantly
  • Understand customer needs and the pain they are experiencing related to tax automation
  • Understand competitive products

You would be a great fit if

  • You are fully proficient in English. Written and spoken, we are from around the world, but we work in English.
  • You have a strong sense of ownership, care about what you build, and do the right thing that serves your customers.
  • You’re a builder at heart; you like the opportunity of having tons of exposure, making things work for a company long term, and having an entrepreneurial attitude toward anything that comes your way.
  • You are either eager to learn or comfortable scaling and operating large-scale microservices in high-growth environments.
  • You are proficient in a couple of languages; most of our current codebase is in node.js with Typescript and Go on the backend. We use ReactJS on the front end, but we are not married to any tools; we see them as a means to an end.
  • You like to keep your house tidy and clean, and you just can't leave code not covered with a test. Or a feature undelivered. Or dead code rotting in production.
  • You ship fast, continuously, and iteratively, learning each step.
  • You like to use data over opinions to make decisions. And are ok with finding the data yourself when it’s missing.
  • You are comfortable with change, either in priorities, goals and deadlines. You see this more as an opportunity than a hurdle. You are also satisfied with challenging the status quo and pushing for change.
  • You want to make a severe impact and are excited about working in a high-growth startup.


If you feel you don’t have the whole experience we’re looking for but feel you could be a bit fit and are willing to learn, do apply anyway! We are trying to build a diverse and inclusive team.


We enable companies worldwide to seamlessly handle their taxes when transacting online by providing outstanding products that automate their workflows. To build exceptional products, we are aware that we need great people. We offer a competitive base salary for this position and remain open to a specific range depending on candidates' experience. Also, we provide attractive equity to keep everyone positively incentivized.

We're a company filled with talented, energetic, and motivated people from all backgrounds who bring in their different perspectives to help us on our mission to make taxes simple. We have a distributed team in more than 20 countries worldwide and you can read more on how we live our values and what inspires us to do amazing things together:

In 2024 and 2023, Fonoa has been ranked Sifted’s Rising 100: Rising 100 2024 and The ultimate B2B SaaS startup list

Sounds interesting? Please learn more reasons why you should join us.