They come from insecure shortcuts that look correct at first glance.
This is a real pattern I’ve seen in early-stage SaaS codebases: token systems that work, but silently leak sensitive data.
Insecure implementation
Common issues include:
- MD5 or weak hashing for token generation
- Hardcoded secrets inside code
- Session tokens printed in logs
- Returning raw user identifiers alongside tokens
- No validation on Authorization headers
Everything “functions”, but nothing is actually safe.
Secure implementation
A production-safe version typically includes:
- Strong entropy generation (randomBytes)
- Secrets stored in environment variables
- HMAC-based signing instead of weak hashing
- No logging of sensitive values
- Minimal token exposure (IDs instead of raw tokens)
- timingSafeEqual for verification
The functionality stays the same.
The risk surface changes completely.
The real issue
This isn’t a coding problem.
It’s a “copy and ship” problem.
Developers often prioritize speed over structure, especially in early SaaS builds.
Security becomes something to “fix later”… which usually means never revisiting it.
Final thought
Authentication should be designed, not assembled.
Once I started treating it that way, most of these issues disappeared from my workflow.
I wrote more about this transition in:
From Vibe Coder to SaaS Engineer
It’s a breakdown of how I approach building production-ready SaaS systems from day one.
Top comments (0)