Case Studies

Module 16.1: Case Studies

Estimated time: ~40 minutes

Prerequisite: Phases 1-15 (entire course)

Outcome: After this module, you will understand how Claude Code is applied in diverse real-world scenarios and learn from successful implementations.

1. WHY — Why This Matters

You’ve completed 15 phases. You know the techniques. But do you know how they fit together in real projects?

Theory teaches principles. Case studies show reality. How do solo developers ship SaaS products in months? How do teams scale from 5 to 50 developers without chaos? How do legacy codebases get modernized without rewrites?

The gap between “knowing techniques” and “applying them effectively” is bridged by studying real implementations. Learn from others’ successes AND failures. Shortcut months of trial-and-error by understanding what actually works in production.

2. CONCEPT — Core Ideas

The Case Study Framework

Every case study in this module follows the same structure:

graph TD
    A[Context] --> B[Challenge]
    B --> C[Approach]
    C --> D[Techniques Used]
    D --> E[Results]
    E --> F[Lessons Learned]

    style A fill:#e1f5ff
    style F fill:#fff4e1

Framework Components:

Context: Who, what, team size, constraints
Challenge: Specific problems faced
Approach: High-level strategy chosen
Techniques: Which course modules were applied
Results: Measurable outcomes (velocity, quality, time)
Lessons: What worked, what didn’t, what they’d change

Case Study Categories

Category	Team Size	Primary Focus	Key Constraint
Solo/Indie	1 developer	Maximum individual output	Time, energy
Startup	2-10 developers	Ship fast, maintain quality	Runway, market fit
Agency	10-50 developers	Consistency across clients	Context switching
Enterprise	50+ developers	Scale, compliance, process	Governance, risk
Open Source	Distributed	Community, documentation	Volunteer coordination

How to Learn from Case Studies

Match context first — Find cases similar to your situation
Extract principles, not steps — Adapt, don’t copy blindly
Learn from failures — Mistakes are more valuable than successes
Map to course modules — Connect real results to techniques you learned
Measure your own results — Track before/after metrics

3. DEMO — Step by Step

Case Study 1: Solo Developer — B2B SaaS Invoice Platform

Context: Solo founder (nights/weekends), building invoicing SaaS for Vietnamese freelancers. Budget $500/month, 6-month timeline, 12-15 hours/week.

Challenge: Full-stack work (React + Node.js + PostgreSQL) with limited time. Can’t afford architectural mistakes.

Approach: Invested 8 hours upfront in CLAUDE.md (domain model, templates, 15-min task breakdown). Weekly pattern: Sunday planning with Think mode, weeknights execution, Friday quality review.

Techniques: CLAUDE.md as single source of truth (Phase 4.2), Think mode for architecture (Phase 6.1), cost optimization (Phase 14.4), custom templates (Phase 15.1).

Results: MVP shipped in 4 months (2 months early), 15K lines of code, 92% test coverage, $2K MRR within 2 months, total cost $380.

Lesson: CLAUDE.md investment paid off 10x. Should have added integration tests earlier.

Case Study 2: Startup — Fintech Payment Gateway

Context: 5-person Vietnamese fintech team integrating VNPay/MoMo/ZaloPay with regulatory compliance requirements. 3-month runway.

Challenge: Complex payment APIs, strict compliance (logging, audit trails), team new to Claude Code, high stakes.

Approach: 2-day team training, shared CLAUDE.md with compliance rules, automated quality gates in GitHub Actions.

Techniques: Team-synchronized CLAUDE.md (Phase 10.1), GitHub Actions automation (Phase 11.4), report generation (Phase 13.2), quality assessment (Phase 8.4).

Results: Launched in 10 weeks (2 weeks early), passed regulatory audit first try, zero payment discrepancies, 2x team velocity, onboarding: 3 days → 1 day.

Lesson: Upfront training saved weeks of inconsistency. Automated compliance reports saved 40 hours/month.

Case Study 3: Enterprise — Legacy Java Modernization

Context: Large Vietnamese bank with 15-year-old Java monolith (2.5M lines), 50+ developers, regulatory constraints, cannot do big-bang rewrite.

Challenge: Understand legacy code (original devs gone), incremental modernization without disrupting production, maintain compliance.

Approach: Four-phase plan: Archeology to understand code, custom Skills for banking domain, incremental migration with automated testing, team training.

Techniques: Archeology mode (Phase 9.1), legacy test generation (Phase 9.3), custom Skills for compliance (Phase 15.5), security hooks (Phase 11.3).

Results: 30% modernized in 6 months, zero security incidents, 45% bug reduction in modernized modules, +35% developer satisfaction, clean regulatory audit.

Lesson: Test generation before refactoring prevented regressions. Archeology mode was critical for understanding context.

4. PRACTICE — Try It Yourself

Exercise 1: Find Your Match

Goal: Identify which case study best matches your context and create an action plan.

Instructions:

Review the 3 case studies above
Identify which one closest matches your situation
List 3 techniques you can adopt immediately
Identify 1 mistake from that case to avoid

Expected Result: A concrete action plan based on proven approaches.

💡 Hint

Consider: team size (solo, small, large), project type (greenfield, legacy), primary constraint (time, quality, scale, compliance), your role (IC, lead, architect).

✅ Solution

Example for 3-person startup:

Best match: Case Study 2 (Startup)

3 techniques: (1) 2-day team training (Phase 10.1), (2) Shared CLAUDE.md (Phase 4.2), (3) GitHub Actions quality gates (Phase 11.4)

Avoid: Don’t skip Git conventions — standardize early.

Adaptation: Apply automated checks to performance budgets, not just compliance.

5. CHEAT SHEET

Case Study Framework

Component	Questions to Answer
Context	Who? Team size? Stack? Timeline? Budget?
Challenge	What specific problems? What’s at stake?
Approach	What strategy? What investment upfront?
Techniques	Which modules? How applied?
Results	Before → After metrics? Qualitative wins?
Lessons	What worked? What didn’t? What’d you change?

Match Your Context

Your Situation	Focus On	Key Takeaways
Solo developer	Case 1	CLAUDE.md investment, templates, cost optimization
Small team (2-10)	Case 2	Team training, shared standards, quality gates
Enterprise/legacy	Case 3	Archeology, custom Skills, incremental migration

6. PITFALLS — Common Mistakes

❌ Mistake	✅ Correct Approach
Copy case study exactly without adaptation	Extract principles, adapt to YOUR context and constraints
Focus only on results, skip the approach	Study HOW they got results, not just WHAT results they got
No baseline metrics before starting	Track before/after to prove results (time, quality, velocity)
Skip team alignment and training	If >1 person, invest in training upfront (saves weeks)

7. REAL CASE — Production Story

Meta-Case: How This Course Was Created

Scenario: Senior Android Engineer (12+ years experience, Vietnam-based) creating comprehensive Claude Code course while working full-time.

Problem: Massive scope (55 modules, bilingual EN/VI, 44K-82K words total). Must maintain consistency, ensure every technique is real and tested, write in two languages without losing quality.

Solution: Created CLAUDE.md defining course standards (7-block structure, quality rules). Created module template. Applied every technique taught in the course to create the course content. Used CLAUDE.md (Phase 4.2), Think mode for curriculum design (Phase 6.1), templates for consistency (Phase 15.1), quality optimization (Phase 14.3).

Result: 55 modules following identical structure, bilingual throughout, 100% real examples, practical exercises in every module. Published as open educational resource.

Key insight: Eating your own cooking works. This course was built using the exact techniques it teaches. If they didn’t work in practice, they wouldn’t be in this course.

Next: Module 16.2: Role-Specific Workflows →