Local Base64, Base64URL and data URI workbench
Encode text or small local files to Base64, decode standard or URL-safe Base64 back to bytes, inspect padding and byte length, build a data URI, review the decoded UTF-8 text, and keep the important warning visible: Base64 is encoding, not encryption.
Text and file conversion run in your browser. Do not treat Base64 as secrecy, and avoid pasting live credentials or production tokens into shared screenshots.
Base64 is for transport, not secrecy
Base64 is a way to represent bytes with readable ASCII characters. It is common in APIs, email attachments, Basic Authentication examples, JWT header and payload sections, small data URIs, configuration snippets and debugging logs. It is useful because many systems are comfortable moving text, even when the original value is binary. But Base64 is fully reversible. Anyone who can read the encoded value can decode it, so it should never be used as a password hiding method or security boundary.
This Base64 encoder and decoder is designed for practical inspection. It supports normal Base64, Base64URL, optional padding, UTF-8 text, small local files, byte previews and data URI generation. The goal is not only to convert a value, but to help you understand whether a token is URL-safe, whether padding is missing, how many bytes are involved and whether the decoded output is text or binary-looking data.
How to use the result safely
When you encode text, the output can be copied into an API example, a test fixture or a small data URI. When you decode a value, read the issue list before trusting the text preview. A decoded token may contain JSON, credentials, binary bytes or application-specific data. If the value looks like a JWT section, use a JWT decoder for the full token. If it looks like a password or secret, redact it before sharing.
- Standard Base64 uses letters, numbers, plus, slash and optional equals padding.
- Base64URL replaces plus and slash with dash and underscore for URL and token contexts.
- Padding may be required by some decoders and omitted by many URL-safe token formats.
- Data URI output is convenient for tiny examples, not for large production assets.
- Byte view helps when decoded content is not readable UTF-8 text.
Common Base64 debugging examples
If a webhook contains a Base64 payload, decode it and check whether the result is JSON, plain text or binary. If an API expects Basic Authentication, encode the exact username:password test string and avoid logging the real secret. If a token segment contains dash and underscore, choose URL-safe mode. If a data URI does not render, confirm the MIME type and check whether padding or line wrapping was changed by a copy step.
Common questions
Is Base64 encryption?
No. Base64 is encoding. It does not use a secret key and it does not protect the content.
Why does Base64 sometimes end with equals signs?
Equals signs are padding characters. They help align encoded output to a four-character block. Some URL-safe formats remove them and restore them during decoding.
Can I encode files?
Yes, for small local files. The file is read in the browser and converted to Base64. Very large files are better handled with a local command-line tool.
Is Base64 a form of encryption?
No. Base64 is encoding, not encryption, and is fully reversible by anyone. It hides nothing, so never use it to protect secrets.
Why does Base64 make data larger?
It represents every 3 bytes as 4 ASCII characters, so the output is about 33 percent bigger than the input.
What is URL-safe Base64?
A variant that replaces the + and / characters with – and _ so the encoded string is safe to use inside URLs and file names.
