Base64 Encoder & Decoder — Encode Text Online

How to use Base64 Encoder & Decoder — Encode Text Online

Three simple steps, with your content kept on your device.

Built for useful work

Fast, focused, and made to be clear on every screen.

What is Base64?

Base64 is a binary-to-text encoding that represents binary data using only 64 printable ASCII characters: A-Z, a-z, 0-9, plus, slash, and padding. It exists so data that was not designed for text — images, files, or raw bytes — can travel safely through text-only channels such as email bodies, JSON fields, and URLs.

Because Base64 uses 64 characters to represent 6 bits at a time, the encoded output is about 33% larger than the original binary data. That size overhead is the standard trade-off of any Base64 encoding.

Base64 encode vs Base64 decode

Encoding turns plain text or binary data into the Base64 alphabet, which makes it safe for transport. Decoding reverses the process and restores the original bytes. The two directions are exact opposites: encoding a value and then decoding the result returns the original input.

This tool supports both directions from one interface. Paste text and choose Encode to get the Base64 version, or paste a Base64 string and choose Decode to recover the original content. Whether you need to base64 decode a token or encode a string for an API, the same page handles it.

How the Base64 encoder works locally

Valestiom converts text to Base64 and back entirely in your browser using the built-in TextEncoder and TextDecoder APIs. The input never leaves your device, so the tool is safe for tokens, private strings, and confidential data.

Unicode text is handled with UTF-8 conversion, which means Persian, Arabic, Chinese, and emoji all encode and decode correctly.

Common uses of Base64

Developers use Base64 to embed small images directly inside HTML, CSS, or JSON instead of loading a separate file. It also appears in API authentication tokens, email attachments, and data exchanged between systems that expect ASCII-safe text.

A common workflow is to encode a string, inspect the result, and later decode it to verify the original value — both steps happen instantly on this page.

Base64 is not encryption

Base64 is an encoding, not encryption. Anyone who sees a Base64 string can decode it without a key, so it provides no security for sensitive data. It is a format for transport, not a method of protection.

If you need to protect a value, use a hashing or encryption tool instead. A Base64 encoder only changes the representation of the data; it never hides its content.

Valid input for decoding

A valid Base64 string uses only the standard alphabet plus optional padding with equals signs, and its length must be a multiple of four after padding. Whitespace is ignored, so line-wrapped Base64 still decodes correctly.

Malformed input — stray characters, wrong padding, or truncated strings — is rejected with a clear error instead of producing garbage output.

Reading a Base64 string

Most Base64 strings end with a recognizable signature: an equals sign padding at the end, a length that is a multiple of four, and only characters from the standard alphabet. When you see a value like dGV4dA== you can be fairly confident it is Base64.

The quickest way to read it is to paste it into this tool and choose Decode. The output reveals whether it was plain text, JSON, or binary data, and if the padding is missing the tool reports it as malformed.

Base64 in APIs and tokens

Many APIs exchange Base64-encoded values: JWT tokens store their payload in Base64URL, some authentication headers carry credentials in Basic encoding, and configuration systems embed secrets as Base64 strings.

A developer who works with these systems constantly needs to base64 decode a value to inspect it or base64 encode a value before sending it. Both operations are one paste away on this page, and because it runs locally the token never leaves your browser.

Base64 in web development

Front-end developers regularly meet Base64 in two places: data URIs that embed images inside CSS or HTML, and authorization headers that carry credentials. Inspecting either usually means decoding a Base64 string to see the real value.

The workflow is the same in both cases: copy the encoded value, choose Decode on this page, and read the original text. When you need to produce such a value yourself, choose Encode and paste the result into your code. Both a base64 encoder and a base64 decoder live on this single page, so you can encode base64 text and decode base64 input without switching tools.

Privacy of encoded data

Because Base64 is reversible, any Base64 string is only as private as plain text. A token encoded with Base64 can be decoded by anyone who sees it, so never rely on Base64 to protect a secret.

This tool reinforces that point by doing everything locally: when you base64 encode or decode a value, the data is processed in your browser and never sent anywhere.

Frequently asked questions