Prefix the Bugs in Your Code
Understand what your code is doing and find bugs you didn’t even know existed.
By submitting your email address, you agree to be contacted via email about our products and services. You can unsubscribe at any time.
Prefix is used by over 20,000 developers in more than 140 countries!

Find a bug, you're a hero!
Use Prefix every day while you are writing and testing your code.
- Validate the behavior of your code
- Find hidden exceptions in your code
- Identify slow SQL queries and N+1 problems
- Review the performance of your code
Can I use Prefix?
Prefix is designed for daily use by developers who are developing .NET or Java web applications.
- .NET or Java
- Web Applications
- Windows desktop
- Servers
- GUI applications
- macOS
Note: Prefix currently only works on Windows.
We plan to support .NET Core/.NET 5, Java, Python, Ruby, and Node.js on Windows and macOS as well as PHP on macOS soon.

Download Prefix Now for Free!
By submitting your email address, you agree to be contacted via email about our products and services. You can unsubscribe at any time.
Prefix supports .NET & Java applications running on Windows.
Tour Prefix in 90 Seconds
Feature Highlights
View Your Logs by Request
Stop sorting through messy log files. See the exact log messages for a single web request.

Find Hidden Exceptions
Prefix can instantly show you all the exceptions hidden in your code.

Quickly Spot Suspicious Behaviors
People see things with Prefix they never expected. Why does that web request do 38 database calls?

View SQL Queries
Including SQL parameters, affected records and how long it took to download the result set.

Prefix vs. Standard code profiler
Prefix web request profiler
Captures detailed code-level traces of each web request.

Prefix is designed to be used every day.
Standard code profiler
Provides method and line level performance reporting.

Typically used only when CPU usage is high.
Prefix is perfect to run on your second monitor!
Want to see see Prefix in action?

Prefix vs Retrace
Not sure what the differences are between Prefix and Retrace? No problem!

For your workstation
Lightweight web request profiler
- Used during development
- View details of individual web requests
- Code improvement suggestions
- Save and load old traces
- View traces on remote servers that have Retrace installed
- Compare production to servers in production

For your servers
Developer friendly APM
- Used in QA and production environments
- Centralized logging & error tracking
- Comprehensive application monitoring
- Application & server metrics