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Backend Engineer



Software Engineering
Zagreb, Croatia
Posted on Thursday, June 27, 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. We also care about creating scalable, easy-to-operate, 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 as possible to improve as professionals.
  • We break down complex problems and consistently seek the most straightforward solutions.
  • We take quality and security seriously and factor it into everything we do.
  • We are comfortable with change in terms of 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 with each step.
  • We are comfortable making mistakes. We don’t blame and consider every failure an opportunity to improve.
  • We measure everything, use the data to make decisions, and influence the organization
  • We don’t allow blockers to prevent us from delivery. We step out of our comfort zone to find the solution and collaborate with other teams to move the initiatives forward

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 the backend, we use Node and Go
  • For the frontend, we use ReactJS and Typescript
  • For persistence, we use PostgreSQL and S3
  • 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 large-scale companies to handle tax manually and understand how our technology is changing the status quo
  • Own what you build, with the ability to decide how to build it and the responsibility of operating it in the production environment.
  • Build meaningful products using modern technologies (REST, GRPC, Microservices, etc.) that our customers use and depend on for everyday business (finance, operation, tax and developer teams)
  • Record and collate Terabytes of data from all these operations for long-term storage and future insight
  • Continuously feed the learnings and observations of operating the system back into our products
  • Collaborate with the product team to define the future of our products and deliver value with every release

You would be a great fit if:

  • You are fully proficient in English. Written and spoken, as we are a bunch from around the world, but we work in English.
  • You have a strong sense of ownership, care about what you build, and build 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 for anything that comes your way.
  • You are 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 Go and node.js with Typescript, 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 like to use data over opinions to make decisions. And are okay with finding the data yourself when it’s missing.
  • You value simplicity over complex solutions and always look for novel ways of simplifying the system. You build software without an ego but feel pride and joy seeing your work in production.
  • You prefer to improve the system as a whole and are not fixated on improving local optimums that may not impact the bottleneck.


If 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.