Online URL & Base64 Encoder / Decoder
Free online tool to encode URL, decode URL, convert Base64, and escape HTML entities instantly in your browser.
About The Transformer (URL, Base64 & HTML Encoder / Decoder)
The Transformer is a fast, 100% browser-based string converter. Encode and decode web URLs, Base64 data strings, and HTML entities instantly without sending your sensitive data over any network API.
URL Encode & Decode
Escapes special symbols, spaces (%20), and query params into valid percent-encoded RFC 3986 URI strings for safe HTTP requests and API endpoints.
Base64 Encode & Decode
Converts ASCII text and binary data into 64-character MIME format for data URIs, Authorization headers, and JWT token inspection.
HTML Entity Escape
Escapes reserved HTML markup characters (<, >, &) into entities to prevent XSS injection attacks.
About the Encoder & Decoder
The Encoder & Decoder handles the three escaping schemes developers hit most often: percent-encoding for URLs and query strings, Base64 for binary-safe transport in JSON payloads and HTTP headers, and HTML entity escaping for rendering untrusted text safely. Switch direction with one click to decode a value you captured from a log line, an Authorization header or a redirect URL.
How to use the Encoder & Decoder
- Choose the transformation you need: URL, Base64 or HTML entities.
- Paste your string into the input panel and pick encode or decode.
- Copy the result, or chain it into another transformation.
Frequently asked questions
Is Base64 encoding the same as encryption?
No. Base64 is a reversible encoding designed to represent binary data as ASCII text. Anyone can decode it without a key, so it must never be used to protect passwords, tokens or personal data.
What is the difference between encodeURI and encodeURIComponent?
encodeURI preserves characters that have structural meaning in a URL such as :, /, ? and #, so it is used for a complete URL. encodeURIComponent escapes those characters too, so it is used for a single query parameter value or path segment.
Why does my decoded Base64 string look like garbage?
The input was probably URL-safe Base64, which substitutes - and _ for + and /, or the payload is binary rather than UTF-8 text. Convert the URL-safe characters back first, and remember that compressed or encrypted payloads will not decode to readable text.
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Encoder & Decoder is free to use with no account, no ads and no usage limits. Every calculation runs locally in your browser, so nothing you paste is ever uploaded. See our privacy policy.