Console Errors Test
The Console Errors Test loads any URL in headless Chrome and captures everything that appears in the browser console during page load — errors, warnings, network failures, CSP violations, deprecated API usage and third-party noise. Console output is the canary in the coal mine for site health: persistent warnings often hide real bugs that surface as user-impacting issues weeks later.
What This Tool Checks
- console.error messages
- console.warn messages
- Network failures (failed fetch, blocked CORS, 404 assets)
- CSP violation reports
- Deprecated browser API warnings
- Mixed-content warnings on HTTPS pages
- Third-party script noise
Why It Matters for SEO
Most production sites have dozens of console errors and warnings nobody reads — but persistent noise hides the new errors that matter. Cleaning up console output is a basic hygiene step that lets you spot regressions instantly. Many warnings (deprecated APIs, CSP violations) also predict future breakage when browsers ship the next change.
How to Fix It
Triage every error and warning in this report. Fix first-party issues; report third-party issues to the vendor or remove the script. Strip console.log calls from production builds. Resolve deprecated API warnings before browsers remove the API. Migrate any HTTP asset references to HTTPS.
How It Works
Headless Chrome subscribes to console events during navigation and the first few seconds of page life, then collects every message classified by severity. Each message is reported with source URL, line number and a short categorisation so you can fix the highest-impact issues first.
Common Mistakes to Avoid
- Treating console output as developer-only noise nobody needs to clean up
- Leaving development console.log calls in production
- Ignoring deprecated API warnings until the API is removed
- CSP violations dismissed instead of fixed
- Mixed-content warnings on HTTPS pages (loading HTTP resources)
Quick Checklist
- Zero console.error messages in production
- No console.log left from development
- No deprecated API warnings
- No CSP violations
- No mixed-content warnings on HTTPS pages