Base64 Encoder/Decoder - Convert Text to Base64 and Back Online

Encode and decode Base64 text directly in your browser.

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Local-first
Free limit: Text input

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Base64 is a transport format, not a security feature. It is commonly used in tokens, payloads, and text-based transmission workflows, but it should never be treated as encryption.

Everything runs in the browser, which makes it convenient for quick debugging without exposing data to third-party services.

Common uses for Base64 Encoder/Decoder

Typical tasks this tool is built for.

Decode Base64 strings from logs, APIs, or tokens.
Encode short values for text-based transport.
Test integrations that require Base64 fields.
Inspect encoded payload content during debugging.

How to use Base64 Encoder/Decoder

Step 1. Choose encode or decode mode.
Step 2. For encoded output, choose URL-safe Base64 and whether to include = padding when the receiving system requires it.
Step 3. For a URL-safe value being decoded, enable URL-safe Base64 so - and _ are converted before decoding.
Step 4. Paste the text or Base64 string into the input.
Step 5. Run the conversion and review the output.
Step 6. Copy the result — remember Base64 is not encryption.

Why use this tool?

Encode text to Base64 or decode Base64 back to readable text.
Useful for debugging textual API payloads and testing transport-safe strings.
Runs entirely in the browser for quick checks.
Switch to URL-safe output when an integration expects - and _ instead of + and /.
Copy a completed result or download it as a plain-text .txt file.

Privacy and formats

Encoding and decoding run locally in your browser. Base64 is not encryption — do not use it to hide secrets.

Input: TextOutput: Processed text

Best results with Base64 Encoder/Decoder

Practical tips before you download or share the output.

Base64 increases data size and does not protect secrets. Use real encryption for confidential information.

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Common problems this tool helps with

Situations where this workflow saves time.

Treating Base64 as security — it is encoding only.

A URL-safe value fails to decode - enable URL-safe Base64 when the input uses - and _ in place of + and /.

A copied value contains wrapping spaces or line breaks - decoding removes whitespace, but the remaining characters must still be valid Base64.

Decoded output looks wrong for binary data - this tool uses TextDecoder for text and is not an arbitrary binary-file converter.

Copy output does nothing - clipboard permission or browser support can prevent navigator.clipboard.writeText from succeeding.

Wrong padding — malformed Base64 strings fail to decode.

Binary data pasted as text — some outputs are not human-readable.

Frequently asked questions

Is Base64 encryption?

No. Base64 encodes data for text-safe transport. Anyone can decode it without a secret key.

Is my input sent to a server?

No. Encoding and decoding run locally in your browser.

Why did decode fail?

Check for invalid characters, missing padding, or URL-safe variants. Remove whitespace and try again.

When should I use Base64?

Common cases include debugging textual API payloads and testing systems that expect Base64 fields.

What does URL-safe Base64 change?

For encoded output it replaces + with - and / with _. For decoding, it converts those URL-safe characters back before calling atob.

What does the padding option do?

It controls whether encoded output retains trailing = characters when padding is needed. The decoder can append missing padding for a valid length, but a remainder of one character is invalid.

Does this convert files or binary data?

No. It accepts textarea text only. Encoding uses TextEncoder and btoa, while decoding uses atob followed by TextDecoder; there is no file picker or binary-file workflow.

What can I copy or download?

Copy output uses the browser clipboard. Download .txt creates encoded-base64.txt in Encode mode or decoded-text.txt in Decode mode.

Is there an explicit input-size limit?

The component does not set a character limit for its textarea. Very large inputs are still limited by browser memory and responsiveness.

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How to use Base64 Encoder/Decoder

Step 1. Choose encode or decode mode.

Step 2. For encoded output, choose URL-safe Base64 and whether to include = padding when the receiving system requires it.

Step 3. For a URL-safe value being decoded, enable URL-safe Base64 so - and _ are converted before decoding.

Step 4. Paste the text or Base64 string into the input.

Step 5. Run the conversion and review the output.

Step 6. Copy the result — remember Base64 is not encryption.

Why use this tool?

Encode text to Base64 or decode Base64 back to readable text.

Useful for debugging textual API payloads and testing transport-safe strings.

Runs entirely in the browser for quick checks.

Switch to URL-safe output when an integration expects - and _ instead of + and /.

Copy a completed result or download it as a plain-text .txt file.