Apply the Mikado Method to Untangle a Tax-Engine Class

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Overview

What this challenge is about.

Refactor a tax-engine class into per-country strategies using the Mikado Method and earn a verifiable certificate.

The scenario

The consultancy (around EUR 12M revenue, around 30 active clients) bills on tax-rule-change throughput — every regression costs an emergency hotfix and reputation with regulated clients.

CredentialBlockchain-anchored

ShareableLinkedIn-ready

LanguageEnglish

PaceSelf-paced

The Brief

What you'll do, and what you'll demonstrate.

Decompose a 4,200-line TaxCalculator class into per-country strategies using the Mikado Method, keeping the build green after every commit.

Earning criteria — what you'll demonstrate

Apply the Mikado Method to plan a non-trivial refactor without big-bang risk
Use revert-and-discover to surface hidden prerequisites instead of guessing them
Maintain an always-green build through a multi-week refactor
Document a refactoring journey so a successor can verify and extend it

Program Fit

Where this fits in your program.

Sharpens the same skills your degree expects you to demonstrate.

Refactoring and Code Smell Detection

Master · Software Engineering

Strong alignment

This challenge maps to Refactoring and Code Smell Detection at the Master level. It sharpens the same practical skills your coursework expects — but in a real industry context with actual constraints and deliverables.

Skills

Skills you'll demonstrate.

Each one shows up on your verified credential.

Careers

Career paths this challenge builds toward

Completing this challenge demonstrates skills that transfer directly to these roles:

Career paths this builds toward

Canonical roles

Software Engineer
Software engineers turn intent into code that other people rely on, often without ever meeting them. The craft is broader than the languages — Python, Go, Java rotate in and out of fashion — and centers on judgment: which abstraction to introduce, which test to write first, which review comment matters and which is taste dressed up as principle. AI tools like Copilot and Claude Code accelerate the typing but raise the bar on knowing what to build. Strong engineers care about the people who'll maintain their code in two years, including their future selves. Students drawn to this path often started building things in high school and never stopped. Growth comes from shipping real systems, taking ownership when they break, and reading code written by people better than you.
Software Engineering

One more thing

You can put a credential on your CV by Friday.

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