Base64 Encoder / Decoder

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Encode text to Base64 or decode Base64 back to text in one click. Full UTF-8 support handles emoji and non-Latin scripts, and URL-safe mode produces output you can drop straight into URLs and filenames.

Runs in your browser. Nothing is uploaded. Base64 is encoding, not encryption.

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How the Base64 Tool Works

The tool uses native browser functions with proper UTF-8 handling for accurate two-way conversion.

  1. Pick a mode, choose Encode to convert text to Base64 or Decode to read Base64 back.
  2. Paste your input, the tool encodes text as UTF-8 first so Unicode and emoji survive.
  3. Optional URL-safe, swap plus and slash for minus and underscore and trim padding for URLs.
  4. Copy the result, one click copies the output, and you can feed it straight back in to chain conversions.

When You Need Base64

Base64 shows up constantly in web development and integrations.

  • Data URIs, inline small images, fonts, or SVGs directly in CSS or HTML.
  • APIs and JSON, transport binary-ish data safely inside text-only payloads.
  • Tokens and headers, decode Base64 segments of JWTs and basic auth headers for debugging.
  • Email and webhooks, encode attachments and signatures that must pass through text channels.

Security note: Base64 is reversible by anyone. Never use it to protect passwords, API keys, or personal data.

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When to Use Base64

Base64 is the right tool whenever binary or unsafe-byte data has to travel through a text-only channel. Remember it adds about 33 percent to the data size, and it is encoding, not encryption, so anyone can decode it.

Use case Encode or decode Notes
Data URIs Encode Inline small images, icons, fonts, or SVGs in CSS/HTML to save a request; the 33% overhead makes this worthwhile only for tiny assets.
HTTP Basic Auth Encode / decode The Authorization header sends user:pass as Base64. It is not secure on its own, so always pair it with HTTPS.
Email attachments (MIME) Encode MIME uses Base64 so binary files survive text-only mail transport intact.
Embedding small assets Encode Bundle a logo or sprite into JSON or a config file when a separate file is impractical.
Inspecting JWTs Decode JWT header and payload segments are URL-safe Base64; decode them to debug claims. Never trust them as a security measure.

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Base64 Encoder / Decoder: FAQ

What can this Base64 tool encode and decode?
It converts pasted UTF-8 text to Base64 and converts Base64 back to UTF-8 text. The output box is read-only, can be copied, and can be moved back into the input with the Use output as input button.
What does URL-safe mode change?
When encoding, URL-safe mode replaces plus with minus, slash with underscore, and removes trailing equals padding. When decoding, it converts those characters back and restores the padding required by the browser decoder.
Will emoji and non-Latin text survive the conversion?
Yes. The implementation converts JavaScript text to UTF-8 bytes before encoding and reconstructs UTF-8 text after decoding. Accented characters, emoji, and non-Latin scripts should round-trip when the original data is valid UTF-8 text.
Why does decoding return an Invalid Base64 input error?
The input may contain characters outside the selected Base64 alphabet, have an impossible length, or include an unrelated prefix such as a data URI header. Select URL-safe mode when appropriate. Invalid UTF-8 byte sequences are displayed with replacement characters rather than rejected.
Why are equals signs added to some Base64 values?
Standard Base64 uses one or two equals signs to pad output to a length divisible by four. They are part of the encoding format, not encrypted data. URL-safe values often omit them, and this tool restores missing padding while decoding.
Does this tool encode uploaded files or arbitrary binary data?
No. It accepts text in a textarea and decodes the result as UTF-8 text. It does not provide a file picker or preserve arbitrary binary bytes as a downloadable file. Use a byte-aware file encoder for images, archives, or other binary formats.
Can Base64 protect passwords, tokens, or confidential content?
No. Base64 is reversible encoding, not encryption or hashing. Anyone with the value can decode it. Do not paste secrets into tools you do not control, and use established encryption or password-hashing methods for security.
Is the text I enter sent to Web Aloha?
No. Encoding, decoding, swapping, and copying run in the browser with native JavaScript APIs. The tool makes no conversion request to a Web Aloha endpoint, so the pasted input and generated output are not uploaded by this feature.