VAT compliance on autopilot — at European scale.
Six years. Eight engineers. €2.1 billion in processed transactions. This is what it looks like to build infrastructure that grows with a company.
About the Project
One platform. 27 countries. Every transaction accounted for.
Hellotax is an all-in-one VAT compliance platform for online sellers operating across Europe. It pulls transaction data from multiple sources — Amazon, other marketplaces, ERP systems — classifies it against the VAT rules of each EU country in real time, and generates the reports that tax authorities require.
Recommended by Amazon. Trusted by thousands of sellers. Processing over €2.1 billion in taxable transactions to date.
“One of a kind in Europe.”
When Cubicfox joined the project, Hellotax was an idea on paper. Today it’s the infrastructure behind some of the continent’s most active cross-border sellers.
History of Partnership
Six years, one direction.
2018
First meeting
A startup with a concept and no codebase. We took on the challenge of building it from scratch.
2019
First version live
The core VAT calculation engine and dashboard shipped. First paying customers.
2020
Scale up
Transaction volumes grew faster than expected. Team expanded. Architecture revisited for the long term.
2021
Amazon recommendation
Hellotax becomes officially recommended by Amazon. Volume spikes. Infrastructure holds.
2022
8-engineer peak team
At the project's peak, 8 Cubicfox engineers work dedicated on Hellotax. Scrum, sprint reviews, shared team events.
2023–present
Ongoing
VAT regulations keep changing. New EU countries, new rules, new features. We're still here.
The Challenge
The scale of the problem.
We joined when it was all just an idea. After a feasibility study, the scope of the technical challenge became clear — and it was significant.
Data Ingestion at Scale
Synchronizing sales and goods movement data from multiple marketplaces simultaneously — Amazon MWS, other platforms, ERP systems — with no tolerance for data loss or duplication. At 70M+ transactions, even a 0.1% error rate means 70,000 mis-filed tax events.
Real-time VAT Classification
Every transaction must be classified against the correct VAT rate for the correct country at the correct point in time. European VAT rules differ by country, by product category, and change regularly. The algorithm has to be both fast and perfectly accurate.
27-Country Regulatory Compliance
Each EU member state has its own filing format, deadline calendar, and submission protocol. The system must generate country-specific reports without any human intervention — and update automatically when rules change.
Performance Under Load
VAT calculations and quality checks run continuously in the background — but the user-facing dashboard must remain responsive at all times. Processing intensity cannot leak into UX degradation.
The Solution
Engineering for correctness, designed for simplicity.
The brief was deceptively simple: make VAT compliance invisible to the user. Everything complex happens in the background — the interface just shows you what you need to know.
01
Google Cloud Platform + Kubernetes
We designed the infrastructure on GCP from day one, using containerized microservices managed by Kubernetes. Calculation workloads scale horizontally during peak periods without affecting platform availability — and individual services can be updated or replaced without downtime.
02
Decoupled calculation engine
The VAT engine (Java / Spring) runs entirely separately from the user-facing application (PHP / Phalcon + Vue.js). Calculation jobs are queued and processed asynchronously — the user sees results, not the work happening to produce them.
03
Regulatory update pipeline
We built a structured process for absorbing VAT rule changes across 27 countries. When regulations update, the change is isolated to the affected country's classification module — it doesn't touch the rest of the system.
04
Agile at scale
As the team grew to 8 engineers, we introduced a dedicated scrum master and formalized sprint cadences. This kept delivery velocity high even as complexity increased.
Numbers that speak for themselves.
Their work goes far beyond development — we’ve been working together as a team for years, from brainstorming initial ideas to the most meticulous implementation. Together we built software used worldwide by Amazon sellers for their tax returns.