JZB Decoder by ravidor

Decode jzb= URL payloads in Firefox DevTools. JZB Decoder watches network traffic for requests containing a jzb= query parameter, decompresses the zlib JSON, and shows readable results in a Decipher JZB panel. All decoding happens locally in your browser.


jzb is a transport format for compressed JSON embedded in a URL query parameter. Payloads are usually:

• URL-safe base64
• zlib-compressed JSON
• Often an array of analytics or telemetry events

JZB Decoder is format-specific, not product-specific. It decodes the payload format itself and does not depend on any vendor SDK, API, or backend.

• Auto-capture — Watches finished network requests whose URL contains jzb=
• Decode — Handles URL-safe base64, zlib decompression, and JSON parsing
• Request list — Shows captured requests with event name or type when present
• Search and filter — Filter by label, URL, method, and common event fields
• Pretty JSON — Readable output with highlighted key fields
• Copy JSON — One-click copy of the decoded payload
• Paste cURL — Decode requests copied from the Network tab

1. Install the add-on
2. Open DevTools on any page
3. Select the Decipher JZB panel from the DevTools tab bar
4. Open the Network tab at least once (required for auto-capture on Firefox)
5. Browse or trigger traffic that includes jzb= in the request URL
6. Select a captured request to view the decoded payload

For manual decoding, open Paste cURL, paste a copied Network request, and click Decode.

• Decoding happens locally in your browser
• No host permissions or broad site access
• No analytics, accounts, or remote servers
• Captured data stays in DevTools memory for the current session and is cleared when you click Clear or close DevTools

Treat decoded output as sensitive. Payloads may include visitor IDs, account IDs, URLs, or other event properties from the sites you inspect.

• Frontend and full-stack developers debugging analytics instrumentation
• QA engineers validating event payloads during releases
• Support and solutions engineers investigating customer-reported tracking issues
• Anyone who regularly inspects jzb= network traffic in DevTools