Encoders & Decoders

Base64 turns binary data into plain ASCII text so it can pass through systems that only handle text: JSON payloads, email bodies, HTML attributes, HTTP headers and environment variables. You run into it when you inline a small icon into CSS, read a JWT, inspect an email attachment, or store a file in a database column that only accepts strings.

These tools cover the common cases. Encode text to Base64, decode a Base64 string back to readable text, turn an image file into a data URI for an img tag or a CSS background, and convert a Base64 string back into an image you can view and download. The image tools show the resulting size. Check that number before you inline an image: Base64 adds roughly 33%, so a 30 KB PNG becomes about 40 KB of text.

HTML entities solve a related problem with a different alphabet. The encoder escapes <, > and & so a stray bracket renders as a character instead of opening a tag. The decoder turns a page full of &amp;amp; and &amp;#8217; back into readable punctuation, which covers most of what you need after a CMS export or a scrape.

Everything runs on the browser's built-in APIs, so files stay on your machine. That matters when the image is a customer document or the text is a credential.