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Utilnivo

Developer

Base64 Encoder & Decoder

  • Browser-based
  • No signup

Convert text to Base64 or decode Base64 back to text. Encoding uses UTF-8, and decoding accepts standard or URL-safe Base64. Results update live and stay in your browser.

Base64 encodes binary data as ASCII-safe text for JSON payloads, data URLs, and email MIME parts. It is encoding, not encryption—anyone with the string can decode it. Do not Base64-wrap secrets thinking they are hidden.

When decoding, invalid padding or non-Base64 characters produce errors rather than partial output. Strip whitespace from pasted strings if decoding fails unexpectedly.

Data URLs can exceed size limits in HTML attributes—host the asset normally when the encoded string grows beyond a few kilobytes.

URL-safe Base64 variants replace `+` and `/` with `-` and `_`—confirm which alphabet your API expects before pasting into production configs.

When debugging JWTs, decode the header and payload segments here, then use JWT Decoder for a structured claim view with expiry highlighting.

Binary files pasted as text will corrupt on encode—use File Checksum or a dedicated tool when the input is not UTF-8 text.

Line-wrapped PEM certificates decode cleanly after you remove header/footer lines and join the body into one continuous string.

Padding `=` characters at the end are required for some decoders—re-add them if you trimmed trailing equals signs while copying.

100% Client-Side

Your data never leaves your computer.

How to use this tool

1. Choose Encode or Decode mode. 2. Paste input text or Base64 into the editor. 3. Read the output in the results panel. 4. Use Copy to copy the result, or Use result as input to chain operations. 5. Click Clear to start over.

Worked example

Example: encode Hello gives SGVsbG8=; decoding SGVsbG8= returns Hello.

When to use this

  • Debugging data URLs or MIME email parts.
  • Inspecting Base64 segments before JWT assembly.
  • Encoding small UTF-8 strings for API examples.
  • Decoding `data:image/png;base64,...` payloads in the browser.

Common examples

  • UTF-8 email header value → Base64 for debugging MIME parts.
  • Small JSON claim → Base64 segment inspection before JWT assembly.
  • Data URL prefix stripped → decode image bytes from `data:image/png;base64,...` payloads.
  • Small SVG icon → data URL for inline HTML email test.
  • UTF-8 string with emoji → Base64 for API fixture matching production encoding.

What people search for

  • base64 encode decode
  • base64 encoder online
  • base64 decoder
  • encode string base64
  • base64 converter

Common mistakes

  • Confusing URL-safe Base64 with standard Base64 padding.
  • Encoding binary files by pasting raw bytes as text.
  • Forgetting UTF-8 vs Latin-1 when decoding non-ASCII text.
  • Treating Base64 as encryption—it is encoding only.

Related long-tail tasks

  • decode JWT payload after Base64 step
  • convert Base64 image to downloadable file
  • encode JSON claim for manual JWT test
  • compare hex vs Base64 representation
  • format JSON inside decoded Base64 string

How it works

Choose Encode or Decode, then paste or type text. Encoding converts UTF-8 text to standard Base64. Decoding accepts standard or URL-safe Base64 (with optional whitespace) and returns the original text. All processing runs in your browser.

Limitations

Results are based on the inputs you provide and may not cover every edge case. This tool is for general use and is not professional advice.

Privacy and file handling

Your data is processed in your browser and is not uploaded to our server.

Specialized Base64 Encoder & Decoder guides

Explore focused guides for common searches—each page reuses this base64 encoder & decoder with different examples and FAQs.

Frequently asked questions

Can I encode Unicode text?

Yes. Text is encoded as UTF-8 before Base64 conversion, so characters like accents and emoji are supported.

Does decoding support URL-safe Base64?

Yes. Decoding accepts standard Base64 and URL-safe variants that use - and _ instead of + and /. Whitespace is ignored.

Is my text stored?

No. Encoding and decoding run locally in your browser and text is not stored.

Part of these workflows

This tool is one step in a longer job. Jump straight to your step or open the full workflow guide.

Related tools

Related pages

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