HTTP & Security Header Tools

CSP Tester

CSP Tester tests a Content-Security-Policy against a list of resource URLs and shows which would load and which would be blocked.

Client-sideRuns entirely in your browser — your data never leaves your device.

CSP Tester is a free HTTP & Security Header Tools utility that runs entirely in your browser — nothing you enter is uploaded.

Resource test

How to use CSP Tester

  1. Enter or paste your text into the input field to begin.
  2. Use the Content-Security-Policy, Resource URLs (one per line) settings to control the result.
  3. Watch the output update instantly while you adjust the text.
  4. Finish by choosing Copy to take the output with you.

About this tool

There is no server behind CSP Tester. CSP Tester handles your input locally and returns the result instantly, with no sign-up.

It is designed to do one job well and stay out of your way. Nothing you enter is uploaded, and it keeps working offline once the page has loaded.

Frequently asked questions

What is CSP Tester for?

CSP Tester lets you check your input right in the browser using the Content-Security-Policy, Resource URLs (one per line) controls, with the result shown instantly and nothing uploaded.

Do I need an account for CSP Tester?

No — CSP Tester needs no account, sign-up or installation.

Is my input private in CSP Tester?

Yes — your input never leaves your device; CSP Tester does all the work in your browser.

Can I use CSP Tester without a connection?

Yes — after the first load CSP Tester runs entirely offline.

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