3 Fatal Mistakes "Vibe Coders" Make

Introduction

AI has fundamentally changed software engineering.

Five years ago, building a web app required months of work. Today, you can describe an idea in natural language and have a working prototype in hours.

This is incredible. The velocity you can achieve is unlike anything we've seen before.

But it comes with a catch.

When you let AI do the heavy lifting without an engineering mindset, you're trading immediate velocity for hidden technical debt. You're shipping features without thinking about security. You're deploying infrastructure without understanding what breaks when.

We call this "vibe coding"—writing code based on vibes, on what seems good, on what the AI generated without a deeper engineering perspective.

Vibe coding works great for prototypes and MVPs. But the moment real users interact with your app, vibe coding becomes dangerous.

This guide covers the three fatal mistakes vibe coders make and how to avoid them.

Mistake #1: Ignoring Basic Security Vulnerabilities (Priority 1)

The Problem:

AI assistants are optimized for making things work, not making things secure. They'll happily generate code that ships faster but opens security holes wide open.

Hard-Coded Secrets

Never put API keys in your code. Use environment variables instead.

Missing Row-Level Security (RLS)

If using Supabase, enable RLS policies on all tables with user data.

S3 Buckets Left Public

Cloud storage should be PRIVATE by default. Use signed URLs for public files.

Security Audit Checklist:

• No hardcoded credentials
• All secrets in environment variables
• RLS enabled on sensitive tables
• Cloud buckets are private
• Authorization enforced on all APIs

Mistake #2: Flying Blind Without Observability

The Problem:

AI will generate working code, but it won't generate the monitoring infrastructure to understand how that code behaves in production.

Two-Tier Observability Framework

1. System Metrics (Infrastructure health)

   • API error rates
   • API latency
   • Database performance
   • Server resource usage

2. Product Analytics (User behavior)

   • How far users scroll
   • What buttons users click
   • Where users drop off
   • Feature usage patterns

You can't fix what you can't see. Invest in both system and product observability.

Mistake #3: Not Understanding Your Scale Ceiling & Costs

The Problem:

You build an app locally, it works great. You deploy it to production, still great. But then your app goes viral, and suddenly:

• Getting paged because the database is locked up
• Getting a $40,000 cloud bill
• Cascading failures because you've hit infrastructure limits

All because you never asked: "How many concurrent users can this handle? How much will it cost if we 10x?"

Every infrastructure has breaking points. You need to know:

• How many concurrent users can your app handle?
• What's the cost at 1x, 10x, 100x traffic?

Calculate your scale ceiling BEFORE launch, not when it breaks.

Before You Ship Checklist

PRIORITY 1: SECURITY

• No hardcoded secrets
• RLS enabled on tables
• Buckets private
• Authorization on all APIs

PRIORITY 2: OBSERVABILITY

• Error tracking active
• API latency monitored
• Product analytics implemented
• Alerts configured

PRIORITY 3: SCALE

• Load tested at 10x traffic
• Scale ceiling calculated
• Cost projections reviewed
• Scaling runbook documented

Related Guides

For comprehensive security practices, see The Only Pre-Deployment Checklist You Need. For understanding infrastructure limits, see System Evolution: How to Scale Your Infrastructure.

Also review Platform Stability: Is Software Less Reliable Now? to understand how to build defensively.

Key Takeaways

1. Vibe coding is great for speed, dangerous without engineering discipline
2. Security isn't optional - A fast, broken, hacked app is worthless
3. You can't fix what you can't see - Invest in observability
4. Scale matters - Understand your breaking points and costs
5. Different code deserves different rigor - Experiments vs core logic

For security guidance, refer to the OWASP Top 10 and the OWASP Web Application Security Testing Guide.

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Remember: The difference between a prototype and a production app isn't the code—it's the thinking. Use AI to code faster. Use your engineering brain to ship responsibly.