Encoding & Decoding Tools
Updated June 2026 · 100% client-side — your data never leaves your browser.
Encoding is how data survives the trip between systems that each have their own rules about which characters are safe. A URL can't contain a raw space, an HTML page can't contain a bare angle bracket, and a binary image has to become text before it can live inside a JSON field. This hub collects the encoders and decoders you reach for when data needs to cross one of those boundaries.
From Base64 (for text and images) to URL percent-encoding, HTML entities, and JSON Web Tokens, each tool converts in both directions and shows the result the instant you type. Because everything runs in your browser, you can safely decode a JWT containing user claims or Base64-encode a private asset without it ever touching a network.
Encoding is not encryption — Base64 and percent-encoding are reversible transformations, not security. These tools make that visible: decode any token or string to inspect exactly what it carries, which is invaluable when you're debugging an auth flow or a malformed query string.
When to use these tools
- Inspecting the header and payload of a JWT to debug an authentication or expiry issue.
- Embedding a small icon directly in CSS or HTML as a Base64 data URI.
- Fixing a broken URL where spaces or special characters weren't percent-encoded.
- Escaping user-generated text into HTML entities to prevent it from breaking markup.
- Decoding a Base64 string returned by an API to see the original text or image.
Tools in this category
Frequently asked questions
Is Base64 a form of encryption?
No. Base64 is an encoding, not encryption — it transforms binary data into ASCII text so it can travel through text-only channels. Anyone can decode it instantly, so never use Base64 to hide secrets. Use it for transport and embedding, and use real cryptography for confidentiality.
Does decoding a JWT verify its signature?
No. The JWT decoder reads and displays the header and payload so you can inspect claims and expiry, but it does not verify the cryptographic signature. Signature verification requires the signing key and should happen on your server, never in a public browser tool.
What's the difference between URL encoding and HTML encoding?
URL encoding (percent-encoding) makes text safe inside a URL or query string, turning a space into %20. HTML encoding turns characters with special meaning in markup — like < and & — into entities such as < and & so they render as text instead of being parsed as tags.
Are my tokens and images sent anywhere?
Never. All encoding and decoding happens locally in your browser. Images you convert to Base64 are read with the FileReader API and never uploaded, and tokens you decode stay on your device.