Free Console Log Scanner & JavaScript Error Detector
Scan browser console logs for JavaScript errors, warnings, and security issues. Detect runtime problems, track suspicious scripts, and identify issues that impact user experience. See exactly what errors your visitors encounter.
Error Detection
Capture all JavaScript errors including uncaught exceptions, syntax errors, and runtime failures
Warning Analysis
Identify console warnings, deprecation notices, and potential issues before they become errors
Security Issues
Detect security warnings, CSP violations, mixed content, and suspicious script behavior
Script Tracking
Track which scripts generate errors and identify problematic third-party code
Real Browser Execution
Uses headless Chrome to execute JavaScript and capture actual runtime console output
Stack Traces
Full error stack traces showing exactly where problems occur in your code
All Log Types
Captures errors, warnings, info messages, and debug output from browser console
Console Log Scanner - What Gets Detected & Analyzed
JavaScript Errors
- Uncaught exceptions and runtime errors
- Syntax errors and parsing failures
- Type errors and reference errors
- Promise rejection errors
- Network request failures
- Complete error stack traces
Console Warnings
- Deprecation warnings
- API usage warnings
- Browser compatibility issues
- Resource loading warnings
- Performance warnings
- Third-party script warnings
Security Issues
- CSP violations - Content Security Policy blocks
- Mixed content - HTTPS pages loading HTTP resources
- CORS errors - Cross-origin request failures
- Certificate warnings - SSL/TLS issues
- Cookie violations - SameSite and security flags
- Suspicious behavior - Unusual console activity
Script Source Tracking
- Error source file and line numbers
- Third-party script identification
- Inline vs external script tracking
- Script load order analysis
- Cross-domain script detection
- Malicious script indicators
Console Logs Reveal Hidden Security Issues
The browser console is where JavaScript errors, security warnings, and suspicious script behavior get logged. Many security issues first appear as console errors - CSP violations from injected scripts, CORS errors from data exfiltration attempts, and unexpected errors from malicious code. By monitoring console logs, you can detect attacks and problems that don't show up in source code scans.
Frequently Asked Questions About Console Log Scanning
What is a console log scanner?
A console log scanner analyzes the browser console output when loading your website. It uses a headless browser to execute JavaScript just like a real visitor, then captures all console messages including errors, warnings, security violations, and debug output. This reveals runtime problems that only appear when the page actually executes, not in static code analysis.
Why are console logs important for security?
Console logs reveal security issues that happen at runtime: CSP violations when malicious scripts try to load, CORS errors from data exfiltration attempts, mixed content warnings exposing HTTPS failures, cookie security violations, and unexpected errors from injected code. Many attacks produce console errors before they succeed, making console monitoring an early warning system for security breaches.
What types of errors does this detect?
The scanner detects JavaScript runtime errors (uncaught exceptions, type errors, reference errors), network errors (failed API calls, blocked resources), security violations (CSP blocks, CORS failures, mixed content), cookie and storage errors, promise rejections, and third-party script errors. Each error includes stack traces showing the exact file and line number where it occurred.
How can console errors indicate a hack?
Malicious scripts often generate console errors: CSP violations when trying to load external attack code, unexpected errors from poorly-written injection attempts, CORS failures when exfiltrating data to attacker domains, errors from obfuscated or minified malware, and warnings about blocked resources. A sudden increase in console errors, especially security-related ones, can indicate your site has been compromised.
Is this console log scanner really free?
Yes, our console log scanner is completely free with no registration required. You get instant analysis of all console output including errors, warnings, and security violations with full stack traces. For continuous console monitoring with automated error tracking, alerts when new errors appear, and trend analysis across multiple scans, check out our full security scanning platform below.
Want the Complete Picture?
FREEThis Console Log Scan is great for a quick check, but our Full Security Scan gives you a comprehensive security audit in one go.