🚀 From 'Vibe' to Victory: How Spec-Driven Development in Kiro IDE Slashed My Dev Time by 44%
A deep dive into building a full-featured Agile Planning app with zero WebSocket bugs.
When I first used Kiro a few months ago, I was focused entirely on vibe coding. It was fun, but chaotic. Now, after experimenting with spec-driven development (SDD), I'm completely blown away! I strongly suspect Kiro pioneered this structured approach, which was then adopted by other coding agents.
This time, I built a full-featured Agile Planning application with real-time collaboration, GitHub integration, and a collaborative whiteboard. The result?
Complex features like authentication, WebSocket management, and drag-and-drop became surprisingly straightforward.
Here's exactly why the structured "Plan, Review, Execute" model beats "vibe coding" every single time, backed by concrete numbers from the project.
🤯 The Two Worlds of Coding
What is "Vibe Coding"?
You know the drill:
- Open your editor.
- Start typing code.
- "I'll figure it out as I go."
- Realize you forgot crucial edge cases.
- Refactor everything (or leave it messy).
- Repeat.
It feels productive, but it's chaos in disguise. It's building a skyscraper without a blueprint.
Enter: Spec-Driven Development (SDD)
SDD follows a rigorous, structured approach built directly into the Kiro IDE:
- Plan: Write detailed requirements and acceptance criteria.
- Review: Create a comprehensive design document (architecture, data models, properties).
- Execute: Implement with clear tasks and continuous validation against the spec.
I used Kiro IDE, which has built-in support for this workflow, and the difference was night and day.
🎯 The Project: Agile Planning Tool
I built a real-time collaborative planning poker application.
View the Code: Agile Planning Tool on GitHub
| Core Features Implemented | Tech Stack |
|---|---|
| Real-time Planning Poker | Next.js 14 (App Router) |
| GitHub OAuth Authentication | TypeScript |
| WebSocket Collaboration | MongoDB + Mongoose |
| Drag-and-drop Story Management | Socket.IO |
| Collaborative Whiteboard | Playwright (E2E Tests) |
| External Tool Embedding (Miro, Figma) | Shadcn UI |
💡 1. Why Spec-Driven Development Won: Complex Features Became Simple
SDD forces you to think through the entire system before writing the first line of code.
A. Authentication (GitHub OAuth)
| Vibe Coding | Spec-Driven Development |
|---|---|
| Approach: "I'll just add GitHub login... wait, how do I handle tokens? What about session management? Encryption?" | Approach: The spec demands defining security up front. |
| Result: 2 days of debugging and insecure token handling. | Result: Implementation took 2 hours instead of 2 days of debugging. |
Key Requirement: Authentication
Acceptance Criteria:
3. THE System SHALL store encrypted access tokens in the database.
B. Real-Time Collaboration
| Vibe Coding | Spec-Driven Development |
|---|---|
| Approach: "Let's add Socket.IO... oh wait, how do I handle disconnections? What about race conditions?" | Approach: The spec forces planning for high-availability. |
| Result: Production bugs related to race conditions and dropped connections. | Result: Zero production bugs related to WebSocket management. |
Key Requirement: Real-Time Updates
Acceptance Criteria:
3. WHEN connection drops, THE System SHALL attempt reconnection with exponential backoff.
C. Drag-and-Drop Story Management
| Vibe Coding | Spec-Driven Development |
|---|---|
| Approach: "I'll use a library... which one? How do I persist order? What about conflicts?" | Approach: The spec explicitly defines conflict resolution. |
| Result: Janky UX and data integrity issues upon concurrent edits. | Result: Smooth drag-and-drop with zero conflicts. |
Key Requirement: Story Backlog
Acceptance Criteria:
4. THE System SHALL handle concurrent reordering conflicts gracefully.
📊 2. The Numbers: A Quantitative Victory
The biggest win was the dramatic reduction in debugging and refactoring time. Upfront planning saves time, period.
Development Time Comparison
| Approach | Planning | Coding | Debugging | Refactoring | Total |
|---|---|---|---|---|---|
| Vibe Coding | 0h | 40h | 30h | 20h | 90h |
| Spec-Driven | 7h | 35h | 5h | 3h | 50h |
| Time Saved | 40 hours (44%) |
Code Quality Metrics
| Metric | Vibe Coding (Hypothetical) | Spec-Driven (Actual Project) |
|---|---|---|
| Production Bugs | 15+ | 2 |
| Major Refactors Needed | 5 major | 0 major |
| Test Coverage | 40% | 85% |
| Documentation | Sparse and outdated | Comprehensive (The Spec IS the documentation) |
✍️ 3. Testing Became Natural
Because every major feature had pre-written Acceptance Criteria (AC), writing E2E tests was a mere translation process.
An AC like: “WHEN GitHub OAuth succeeds, THE System SHALL create a user session with GitHub profile data.” directly translates into a test block.
test('should complete full estimation workflow', async ({ page }) => {
// Requirement 2.1: Create session
await page.click('button:has-text("New Session")');
// Requirement 6.3: Cast vote
await page.click('[data-testid="poker-card-5"]');
// Verify: Average calculated correctly
await expect(page.locator('[data-testid="average"]'))
.toContainText('5');
});
Result: 20+ E2E tests written with Playwright, providing high confidence and 100% passing smoke tests before deployment.
🛠️ Tools That Made It Possible
The built-in SDD support in Kiro IDE was the catalyst:
- Structured Spec Creation: Used pre-built templates for requirements and design documents.
- Requirement Linking: Ability to link code commits and tasks directly back to the specific requirement they fulfill.
- Test Integration: Running tests directly from the spec view to validate acceptance criteria.
🛑 Common Objections Answered
| Objection | Reality |
|---|---|
| "Specs take too long to write." | False: 7 hours of planning saved 40+ hours of debugging and rework. That's a huge ROI. |
| "Requirements change anyway." | False: Specs make changes easier. You know exactly which linked components need updating. |
| "This only works for big projects." | False: Even a quick, 30-minute spec for a small feature saves hours of rework and edge-case fixing. |
✅ Final Thoughts
After building this project, I can't imagine going back to "vibe coding" for anything serious. The structure, clarity, and confidence that spec-driven development provides is invaluable.
Vibe coding feels fast but is ultimately slow.
Spec-driven development feels slow but is ultimately fast.
The Bottom Line: Give the "Plan, Review, Execute" model a try on your next project. Your future self will thank you for the robust architecture, reduced bug count, and the sheer predictability of development.
What's your experience with structured development approaches? Have you tried spec-driven development? Let me know in the comments!
#agile #typescript #testing #productivity #webdev #nextjs #react #mongodb #playwright #softwaredevelopment
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