Shadow Testing
Mirror your live production traffic—also known as dark traffic testing—and confidently validate new features, services, or deployments.
gor --input-raw :8080 --output-http="http://staging.example.com"

Beyond Simple Traffic Mirroring
GoReplay isn't just another proxy-based solution; it’s a comprehensive platform for reliable shadow testing.
Advanced Traffic Mirroring
Capture and replay production traffic in real-time or asynchronously, ensuring accurate test conditions.
Response Comparison
Track and analyze differences in responses between old and new service versions to catch subtle bugs.
Intelligent Traffic Analysis
Leverage powerful analytics to uncover patterns, peaks, and anomalies in real-world workloads.
Performance Monitoring
Measure latency fluctuations and overall performance changes between your current and future releases.
Custom Middleware Integration
Easily extend GoReplay with custom logic to filter requests, manipulate payloads, or add extra security checks.
Real-time Insights
Keep a pulse on your shadow testing results as they happen—identifying issues before they reach production.
How Shadow Testing Works
Learn how traffic shadowing, or “dark traffic testing,” enables a powerful, low-risk validation strategy.
Capture Traffic
Tap into your network interface with minimal overhead to capture real user traffic—completely transparent to end users.
Process & Modify
Filter, scrub, or alter the requests as needed to ensure compliance, integrate with testing environments, or scale the test load.
Compare & Analyze
Benchmark performance metrics and validate responses. Detect logical flaws before they can impact production.
Why Choose Shadow Testing?
Gain unmatched confidence by observing how your latest changes perform under live conditions.
Zero Production Impact
Perform shadow testing without risk to your live environment, mirroring real traffic into a separate test service or environment.
Real User Behavior
Analyze genuine user interactions that you simply cannot replicate with synthetic data—no more guesswork.
Deep Service Validation
Go beyond spotting exceptions—compare responses and catch logic errors at the core of your application.
No Infrastructure Changes
Tap into existing traffic flows seamlessly, avoiding major code or network configuration overhauls.
Frequently Asked Questions about Shadow Testing
Get answers to the most common questions surrounding traffic mirroring and dark traffic testing.
What is shadow testing?
Shadow testing, also called “dark traffic testing,” involves sending a real-time copy of production traffic to a test environment. This allows you to safely validate new features or services with real-world data without impacting live users.
Will shadow testing affect my live users?
Not at all. Shadow testing works by mirroring traffic silently, so your users remain unaffected. GoReplay operates in a passive listening mode, minimizing overhead and potential interference with your production environment.
Do I need additional hardware or infrastructure changes?
In most cases, no. GoReplay requires minimal configuration. You simply deploy it to capture network traffic and then route mirrored traffic to your test environment—no complex or expensive infrastructure changes required.
Is there a risk of data exposure?
Sensitive data can be masked or anonymized via custom middleware before reaching test services. By applying best practices and secure policies, you ensure full compliance while still benefiting from real production traffic.
Ready to Start Shadow Testing?
Join hundreds of companies who trust GoReplay to keep their applications reliable and future-proof.