How to use Online URL Checker
- Paste or load response headers, cURL -i output or a HAR into Online URL Checker.
- Click Analyze — Online URL Checker processes everything on your device.
- Read the parsed redirect chain and security-header audit that Online URL Checker lays out for you.
About this page
There is no server behind Online URL Checker. Paste the headers, curl -i output or HAR you captured and Online URL Checker maps the hops and status codes locally.
It also audits the final response for security headers such as HSTS, CSP and X-Content-Type-Options. Your input never leaves the page, and no account or install is required.
Frequently asked questions
What does Online URL Checker do?
Online URL Checker lets you check your input right in the browser, with the result shown instantly and nothing uploaded.
Does Online URL Checker cost anything?
No — Online URL Checker is completely free, with no sign-up and no hidden limits.
Is my input private in Online URL Checker?
Yes — your input never leaves your device; Online URL Checker does all the work in your browser.
Why can't Online URL Checker fetch a live URL itself?
Browsers block cross-origin requests (CORS), so Online URL Checker analyzes response headers, curl -i output or a HAR you capture and paste — all locally.
Can I use Online URL Checker without a connection?
Yes — after the first load Online URL Checker runs entirely offline.