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Version: 0.1.0

Frequently Asked Questions

General Questions​

Cookie Lens is a Chrome DevTools extension that makes cookie debugging easier and safer. It provides inspection, editing, parsing, mocking, reporting, and analysis tools directly in DevTools.

Is it free?​

Yes, Cookie Lens is completely free.

Does it work with other browsers?​

Currently, Cookie Lens is available for Chrome and Chromium-based browsers (Edge, Brave, Opera, etc.). Other browsers don't have DevTools extensions yet.

Do I need an account?​

No account, login, or authentication is required. Just install and use.

Check the extension's repository for the latest information on licensing and source code availability.

Installation & Setup​

  1. Open Cookie Lens on the Chrome Web Store.
  2. Click Add to Chrome.
  3. Confirm permissions.
  4. Open any website and press F12 to see the Cookie Lens tab.

Why do I need to grant permissions?​

  • cookies — allows Cookie Lens to read and edit cookies for the site you're inspecting.
  • tabs — allows Cookie Lens to identify which tab you're viewing.
  • webRequest (optional) — only needed if you enable Set-by-request tracking.

You can revoke optional permissions anytime in chrome://extensions.

No. Cookie Lens only runs in the DevTools panel and doesn't execute while DevTools is closed. Minimal performance impact.

Cookies & Privacy​

No. Absolutely not. All cookie data stays on your device. Cookie Lens has no internet access.

Where is my data stored?​

  • Preferences: your Google account (via Chrome's native sync) or locally on your device.
  • Cookies: only in browser memory while inspecting, then forgotten.
  • Session data: cleared on browser restart.

Can I export my cookies?​

Yes. Use the Export tab to download cookies as JSON. You can share or back up this file. You can later Import it back.

Is exporting cookies secure?​

The export is as secure as your device. Downloaded files are in your control. Don't share exported files with untrusted parties (they contain sensitive cookie data).

Yes. Fully functional on localhost, 127.0.0.1, and any local development site.

Yes, but Cookie Lens will warn you about production domains to prevent accidental data loss.

Use the Search box at the top. Type the cookie name, domain, or part of the value. Results filter instantly.

Yes. Click any cookie to open its details, then click Edit. You can change:

  • Value.
  • Domain.
  • Path.
  • Expiration.
  • Secure, HttpOnly, SameSite flags.

What if I make a mistake while editing?​

  • Before saving: click Discard to close without saving.
  • After saving: use Mocking to test with the original value, or:
    • Click the cookie and edit again.
    • Check the Events tab to see the change history.
    • Restore from an export if you saved one earlier.

Can I delete cookies?​

Yes. Click a cookie to open it, then click Delete. Confirm the deletion.

Protected cookies require additional confirmation.

What's the difference between Editing and Mocking?​

  • Editing — permanently changes the cookie (until you manually change it again).
  • Mocking — temporarily replaces the value for testing. Original is preserved and restorable. Resets on page reload.

Use Mocking for testing without permanent changes.

Can I mock multiple cookies at once?​

Yes. Mock each cookie independently. They all replace simultaneously.

Parsing & Decoding​

  • JSON.
  • Base64.
  • JWT (JSON Web Tokens).
  • URL-encoded data.
  • Query strings.
  • Key-value pairs.
  • And combinations (e.g. URL-encoded JSON).

Can I edit decoded values?​

Yes. When editing a parsed cookie:

  1. Edit the decoded value (e.g. change a JSON field).
  2. Click Save.
  3. Cookie Lens automatically re-encodes to the original format.

Cookie Lens can't decrypt encrypted cookies. You'll see the encrypted value. If you can decrypt it separately, paste the decoded value and edit.

  • The format may not be recognized — manual decoding needed.
  • The value may be invalid or corrupted.
  • Check the exact format (e.g. valid JSON syntax?).
  • Try the Custom Parser settings to create a rule for that format.

Reports & Analysis​

What does the Security Report show?​

Security scoring based on:

  • HttpOnly flag — prevents JavaScript access.
  • Secure flag — HTTPS-only transmission.
  • SameSite policy — cross-site control.

Higher score = better protection.

What does the Privacy Report show?​

Privacy concerns like:

  • 3rd-party cookies.
  • Known tracker domains.
  • Cross-site cookies.
  • Long-lived cookies.
  • Sensitive cookie names.

What does the Expiry Report show?​

Cookie lifetime analysis:

  • Expired cookies.
  • Expiring soon (< 1 hour).
  • Buckets: session, 1h, 1 day, 7 days, 30 days, 1 year, long-term.

What does the Size Report show?​

Cookie size optimization:

  • Per-cookie size.
  • Per-domain totals.
  • Browser limits (4096 bytes per cookie).
  • Warnings for oversized cookies.

Can I export reports?​

Yes. Each report tab has an Export button to download as JSON or CSV.

Set-by-Request Tracking​

What is "Set by request" tracking?​

A feature that shows which network request created or updated each cookie. Useful for debugging server-side cookie behavior.

Is it enabled by default?​

No. It's disabled by default and requires explicit opt-in.

How do I enable it?​

  1. Click the settings icon in Cookie Lens.
  2. Toggle Enable Set by request tracking.
  3. Grant the webRequest permission when prompted.

Does it affect browser performance?​

Minimal impact. It only monitors Set-Cookie headers in responses.

What data does it collect?​

Only metadata:

  • Request method (GET, POST, etc.).
  • Request URL.
  • Response status code.
  • Timestamp.

No. Only the cookie name and domain are extracted. The full header is not stored.

Troubleshooting​

  • Refresh the page.
  • Close and reopen DevTools (F12).
  • Restart the browser.
  • Check that Cookie Lens is installed (chrome://extensions).
  • Check that the extension is enabled (toggle switch on).
  • Some cookies may be read-only (server-managed).
  • The server might immediately overwrite your changes.
  • Check the Events tab to see if the change was applied.
  • Try refreshing the page after editing.

My mocked value reverted​

  • Mocks reset on page reload (this is intentional).
  • Re-apply the mock if needed.
  • Or use Edit for permanent changes.
  • Cookies set by the server may reset on page load.
  • Try adding it to the Protected list, or:
    • Edit another cookie instead.
    • The server might be preventing deletion.

Why is my JWT showing as invalid?​

  • JWT format is header.payload.signature.
  • If any part is malformed, it's invalid.
  • Check the original value (copy from Network tab).
  • Some JWTs use custom encoding (not standard JWT format).

Performance seems slow​

  • Cookie Lens itself is lightweight.
  • Slowness may be from:
    • Large number of cookies (100+).
    • Set-by-request tracking enabled.
    • Browser storage issues.
  • Try disabling Set-by-request tracking.
  • Clear browser cache.

Feedback & Support​

How do I report a bug?​

Check the Chrome Web Store listing for the support/feedback channel. Most extensions have a "Report an issue" link.

How do I request a feature?​

Same as above. Feature requests help improve Cookie Lens.

Where can I find documentation?​

You're reading it. Full guides are in the Guides section.

Cookie Lens is a DevTools extension and requires manual interaction (opening DevTools). For automated testing, consider:

  • chrome.cookies API (if you're writing Puppeteer/Playwright tests).
  • document.cookie in console for simple cases.
  • A cookie library for your test framework.

Technical Questions​

No. It's a DevTools extension, not a content script. It doesn't modify or inject code into pages.

No. Cookie Lens leaves no footprint on the websites you visit.

Does it work in Private/Incognito mode?​

Yes, but cookies are per-session in Incognito. Mocks reset when the Incognito window closes.

Does it work on Chrome OS?​

Yes, if Chrome is installed on Chrome OS.

Does it conflict with other extensions?​

No known conflicts. Cookie Lens is isolated and doesn't interact with other extensions.

Data & Backup​

How do I back up my cookies?​

  1. Go to the Export tab.
  2. Click Cookies as JSON.
  3. Save the file to a secure location.

How do I restore backed-up cookies?​

  1. Go to the Export tab.
  2. Click Import cookies.
  3. Select the JSON file.
  4. Review the preview (shows which cookies will be imported).
  5. Confirm.

Will my settings sync to other devices?​

Yes, if you're logged into Chrome. Your non-cookie settings (preferences, custom parsers) sync via Chrome's native sync.

Can I export my settings?​

Not directly. Settings sync automatically via your Google account. To move settings manually, export cookies as JSON and import on the other device.

Getting Help​

Before asking for help:

  1. Check this FAQ.
  2. Read the relevant guide.
  3. Clear your browser cache.
  4. Restart the browser.
  5. Reinstall the extension if necessary.

Still stuck? Check the Chrome Web Store listing for support options.