Base64 / JWT Decoder

Decode base64, base64url and JWTs from a page selection or a paste, with a pretty JSON tree view.

Base64 / JWT Decoder turns encoded strings into readable, colour-coded JSON, right where you find them. Select base64 on any page and a small 🔓 button appears next to it. Click it and the decoded result opens in place as a collapsible JSON tree. You can also right-click a selection, press a keyboard shortcut (Alt+Shift+D by default), or paste straight into the popup. BUILT FOR REAL-WORLD INPUT The strings you meet in logs, dashboards and API responses are rarely clean. This extension handles: • Standard base64 and base64url, with or without padding • Labels and prefixes such as payload_b64=, v1: or Bearer, which are removed automatically • Quotes, line breaks and data: URI prefixes, which are stripped • gzip and zlib payloads, which are decompressed transparently • Percent-encoded values, which are unwrapped • Base64 nested inside JSON, which decodes in place with one click • Binary data, shown as a hex dump, with common file types recognised A PROPER JSON VIEWER • Collapsible, syntax-coloured tree • Filter keys and values as you type • Copy pretty or minified JSON, any single value, or its JSON path • Open large payloads in a full browser tab JWT DECODING Tokens are split into header, payload and signature. Expiry, issue and not-before times are shown as real dates and in plain language ("expired 2 hours ago"), with a clear status badge. Note: signatures are not verified, because that requires the issuer's key. The extension says so on every token. MAKE IT YOURS • Instant decode: skip the button and see the result the moment you select • Light, dark and black & white themes • One switch in the popup turns all page features off without uninstalling • A local history of recent decodes, which you can turn off or clear in one click PRIVATE BY DESIGN Everything is decoded locally in your browser. Nothing you select, paste or decode is ever sent anywhere. The extension asks for access to all sites only so it can offer the decode button next to text you select. You can switch that off at any time.