Although Blazor is an effective framework for creating contemporary C# online applications, I frequently observe the same errors that impair security, performance, and maintainability in real world projects. These are the ten most frequent Blazor coding errors I see in production, along with suggestions for fixing them, based on my years of experience working on enterprise and SaaS Blazor apps.
1. Putting Business Logic Directly in .razor Files
Many Blazor apps start simple, but over time .razor files turn into massive files full of logic.
Why it’s a problem?
Hard to test
- Difficult to maintain
- Poor separation of concerns
- Better approach
Move logic to code-behind files ( .razor.cs )
Or use service classes and inject them into components
"Razor files should focus on UI, not business rules."
2. Ignoring Proper Naming Conventions
Inconsistent naming is one of the fastest ways to make a Blazor codebase confusing.
Common mistakes
Components named test.razor , page1.razor
Methods like DoStuff() or Handle()
Better approach
Use clear, intention-revealing names
InvoiceList.razor , UserProfileCard.razor
Follow consistent casing and suffix rules
Good naming is not optional — it’s a productivity multiplier.
3. Overusing @code Blocks Instead of Reusable Services
Developers often copy and paste logic between components.
Why these hurts
- Code duplication
- Bugs fixed in one place but not others
Better approach
Extract shared logic into services
Register them using dependency injection
Blazor’s DI system is there for a reason — use it.
4. Incorrect State Management
State bugs are subtle and painful.
Common issues
- Relying too much on static variables
- Losing state on refresh (especially in WASM)
- Confusing scoped vs singleton services
Better approach
- Understand component lifecycle
- Use scoped services wisely
- Persist important state explicitly
State management should be intentional, not accidental.
5. Calling APIs Directly from Components Everywhere
Calling APIs inside every component leads to tight coupling.
Why it’s risky
- Hard to mock
- Hard to refactor
- Poor error handling consistency
Better approach
- Create API service layers
- Centralize error handling and retries
Your components will become cleaner instantly.
6. Not Handling Errors Gracefully
Unhandled exceptions in Blazor can break the entire UI.
Common mistakes
- No try/catch around async calls
- No user-friendly error messages
Better approach
- Wrap async operations carefully
- Use error boundaries
- Log errors properly
Production apps must fail gracefully .
7. Poor Folder Structure
Flat or random folder structures don’t scale.
What I often see
- All components in one folder
- No separation between pages, shared components, and features
Better approach
- Clear separation for:
- Pages
- Components
- Services
- Models
Structure is a form of documentation.
8. Ignoring Performance Basics
Blazor performance issues are usually self-inflicted.
Common mistakes
- Heavy OnAfterRenderAsync
- Unnecessary re-rendering
- Large component trees
Better approach
- Use @key correctly
- Minimize re-renders
- Measure before optimizing
Small changes can have a huge impact.
9. Hardcoding Configuration Values
Hardcoded URLs, keys, and flags appear far too often.
Why this is dangerous
- Security risks
- Difficult environment changes
Better approach
- Use appsettings.json
- Environment-specific configuration
- Secure secrets properly
Configuration should never live in UI code.
10. Treating Blazor Like JavaScript Frameworks
Blazor is not React or Angular .
Common mistake
- Forcing JS-style patterns into Blazor
- Ignoring C# and .NET strengths
Better approach
- Embrace strong typing
- Use C# patterns
- Leverage .NET libraries
Blazor shines when you use it the Blazor way .
Final Thoughts
Most Blazor problems are not framework issues they’re coding standard issues .
Once you apply consistent rules for:
- Naming
- Structure
- State
- Error handling
- Performance
your Blazor apps become cleaner, faster, and easier to scale.