What is Instant Decoder & Encoder?
The Instant Decoder & Encoder is a real-time developer utility built to speed up debugging. Instead of switching between single-purpose websites, paste Base64, Gzip, URL, JWT or HTML-encoded data and get formatted output instantly. Built-in format detection analyses your input and picks the right decoder automatically. Decoded JSON is shown as a collapsible, searchable tree.
How to use Instant Decoder & Encoder
Paste the encoded value into the input panel. Leave the format on Auto to let the tool detect it, or pick a specific format from the toolbar. Switch to Encode to go the other way, then copy the result with one click.
Key features
- Automatic format detection for Base64, JWT, URL, Gzip and HTML entities
- Interactive, searchable JSON tree for decoded payloads
- JWT header, payload and expiry inspection
- Encode and decode in both directions
- Works offline once loaded
- 100% client-side — nothing is uploaded
Supported formats
Base64 encoding
Encodes binary or text data to Base64 and decodes it back. Useful for config payloads, file uploads and data URIs.
Gzip compression
Compresses strings into Gzip represented as Base64, and decompresses raw compressed payloads instantly.
JWT (JSON Web Tokens)
Splits a JWT into readable header, payload and signature, with automatic expiry checks.
URL (percent) encoding
Converts special characters to percent-encoded strings that are safe for URLs, or back again.
HTML entity encoding
Encodes characters like < and > into HTML entities, or decodes them to display raw text.
Frequently asked questions
What is the Instant Decoder & Encoder?
A unified developer utility that automatically detects, decodes and encodes common data formats: Base64, URL-encoded strings, JSON Web Tokens (JWT), Gzip compressed data and HTML entities.
How does automatic format detection work?
In Auto mode the tool inspects the structure of what you paste. A string with exactly two dots is treated as a JWT, percent signs indicate URL encoding, and so on. Otherwise it falls back to text or JSON formatting.
Is my data sent to any servers?
No. All decoding and encoding runs in your browser. Keys, tokens and credentials you paste never leave your machine.
Does this tool work without an internet connection?
Yes. Once the page has loaded, every feature of the Instant Decoder works offline.