Specification-First Refactor of a Payments Module

FreeVerified credential4 weeksAdvanced

Overview

What this challenge is about.

Specification-First Refactor of a Payments Module. Advanced challenge in code. Writing production code that solves real engineering problems, earn a blockcha...

CredentialBlockchain-anchored

ShareableLinkedIn-ready

LanguageEnglish

PaceSelf-paced

The Brief

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

Specify a critical 4,000-line payments module before refactoring it, and prove the refactor was safe with measurable metrics.

This is not a coding exercise. It is the work a software engineer does between a Jira ticket and a merged PR. That distinction matters to every hiring manager who has seen candidates solve LeetCode problems and none who have shipped production code under real constraints.

When you finish, you will have something most graduates do not: a real-world deliverable, verified by Ewance, that you can show to a hiring manager and say "I did this. Here is the proof."

Earning criteria — what you'll demonstrate

Write a precise specification using preconditions, postconditions, and invariants
Use characterization tests to lock in legacy behavior before refactor
Measure refactor success with concrete code-quality and flow metrics
Sequence a refactor in small commits that stay green

Program Fit

Where this fits in your program.

Sharpens the same skills your degree expects you to demonstrate.

Aligned coursework coming soon.

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

Backend Engineer
Behind every app a user touches, there's a quieter system doing the actual work — routing requests, holding state, refusing bad input politely. Backend engineers build and care for that hidden layer. The role is part craft, part diplomacy: you're designing APIs that other engineers will lean on for years, and a careless schema choice can echo through a company for a long time. Good work here looks like code that's boring in the best way — predictable under load, easy for the next person to read, observable when something breaks. Students grow into this role by getting comfortable with Python or another server language, then learning how databases really behave when traffic spikes.
Software Engineering

One more thing

You can put a credential on your CV by Friday.

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