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Base64 Encoder / Decoder

User Guide · Version 2.0.1

Base64 Encoder and Decoder encodes, decodes, inspects and transforms text and files in many formats. This guide walks through everything you can do.

Contents
  1. Getting Started
  2. Text
  3. File
  4. Batch
  5. Pipeline
  6. JWT
  7. Image Preview
  8. Diff
  9. Dev Tools
  10. Folder Watch
  11. History
  12. Settings
  13. Tips

1. Getting Started

When you open the app you'll see a list of sections down the left side. Click a section to switch to it. Most sections share the same simple idea: put something in, choose how to process it, and get a result.

At the bottom of the side panel there are two small buttons:

  • Sun / moon — switches between light and dark theme. Until you choose, the app follows your Windows light/dark setting; once you pick one, it's remembered the next time you open the app.
  • Info (i) — opens the About dialog, which shows the product version and a link to the product website.

A few terms used throughout:

FormatThe encoding to use (Base64, Hex, etc.).
VariantA flavour of a format (for example Base64 Standard vs URL-safe).
EncodeTurn your data into the chosen format.
DecodeTurn formatted data back into the original.

2. Text

The everyday encoder/decoder.

1
Pick a Format (and a Variant if one is offered).
2
Choose the Text encoding if needed — UTF-8 is the right choice almost always. Use UTF-16 or ASCII only if you specifically need them.
3
Type or paste into the Input box.
4
Click Encode → or ← Decode. The result appears in Output.

Buttons

  • Detect — not sure what you're looking at? Paste it and press Detect. The app guesses the format (Base64, Hex, a JWT, a data URI, and so on) and decodes it automatically.
  • Swap — moves the output back into the input, so you can chain operations.
  • Clear — empties both boxes.
  • Copy — the chip on top of the Output box copies the result to the clipboard.
  • Save bytes… — appears after you decode something. It saves the exact decoded bytes to a file. Use it when the result is binary (an image, a zip and so on): the Output box can only show an approximation of binary data, and the app tells you when that's the case.

Keyboard shortcuts: Ctrl+Enter encodes and Ctrl+Shift+Enter decodes. Base64 that's missing its trailing = padding is decoded anyway. Very large results are shown shortened in the Output box, but Copy and Save always use the full result.

Each editor has a small footer that shows the number of characters in that box and a Clear link for emptying just that side. Below both boxes you'll see the size of the input and output and, when you decode something binary, a guess at what kind of file it is (for example "PNG image").

Formats at a glance

FormatUse it for
Base64The most common encoding for binary data in text. Variants: Standard, URL-safe (safe in links), MIME (wrapped lines), PEM (certificate-style blocks).
Base32Case-insensitive encoding; handy for codes people read or type.
Base58Compact, no look-alike characters — used by Bitcoin and similar.
Base85More compact than Base64. Ascii85 and Z85 flavours.
HexPlain hexadecimal. Decoding ignores spaces and line breaks.
URL encodingMake text safe inside a web address (%20 or + for spaces).
HTML entitiesEscape characters like <, >, & for web pages.
ROT13A simple, reversible letter cipher.

3. File

Encode or decode a whole file.

1
Choose Encode or Decode and pick a Format.
2
Set the Input file — click Browse… or drag a file onto the panel.
3
The Output file is suggested automatically; change it if you like.
4
Tick Preserve timestamps & attributes to copy the original file's dates and hidden flag onto the result. (The default comes from Settings.)
5
Click Run. A progress bar appears; large files can be cancelled mid-way.

When decoding, the suggested name keeps the original extension: photo.png.b64 becomes photo.decoded.png. Formats other than Base64 Standard can convert files up to 256 MB; Base64 Standard handles files of any size.

The output file only appears once the conversion has finished successfully. If you cancel, or the input turns out to be invalid, any existing file with that name is left untouched. The output must be a different file from the input. If you close the app while a conversion is running, you'll be asked whether to stop it first.

4. Batch

Process many files in one go.

1
Choose Encode or Decode, a Format, and what to do if the output already exists (overwrite, skip, or fail).
2
Add files with Add files… or by dragging them onto the panel.
3
Optionally set an Output folder (leave it empty to save each result next to its source). The folder is created if it doesn't exist yet.
4
Click Run. Each file shows its own status — done, skipped, or an error.

If two files would produce the same output name (for example data.bin from two different folders), the second one gets a number added, such as data.bin (2).b64, so nothing is overwritten. The file list is locked while a batch is running.

5. Pipeline

Chain several steps together and run them as one — the most powerful section.

1
From the Add step row, pick a transform and a direction (Forward = encode/compress, Inverse = decode/decompress), then click Add.
2
Repeat to build a chain. Use ↑ / ↓ to reorder and Remove to delete a step.
3
Or pick a preset and click Load preset for a ready-made chain.
4
Put your starting text in Input and click Run pipeline.

Each step shows its output, and the final result appears in Output (with a Copy button). If the result is binary, it's shown as Base64 and the heading says so. Available steps include every encoding format plus Gzip, Deflate, Brotli compression and JSON pretty-print.

Example: decode a compressed, Base64-wrapped value from a URL by chaining URL-decode → Base64-decode → Gunzip → JSON pretty-print.

6. JWT

Inspect a JSON Web Token.

1
Paste the token (the xxxxx.yyyyy.zzzzz string) into the box.
2
Click Decode.

You'll see the token's header and payload as readable JSON, and a summary of its timing claims — including whether it has expired. (The app reads the token; it does not check the signature.)

7. Image Preview

See an image that's stored as text.

1
Paste a Base64 image or a data: URI into the box.
2
Click Render.

The picture is shown along with its type and dimensions. If the text isn't a valid image, you'll get a short explanation.

8. Diff

Compare two pieces of text.

1
Paste the original on the left and the changed version on the right.
2
Click Compare.

Differences are highlighted line by line — added lines in green, removed in red, changed in amber — with a summary of how many lines changed. The two result panes scroll together.

9. Dev Tools

Handy extras for developers.

  • HTTP Basic auth — enter a username and password (hidden as you type; click the eye to show it) and click Build header to get the Authorization: Basic … value, or paste a header into the header box (the whole Authorization: Basic … line is fine) and click Decode header to recover the username and password.
  • Code snippet / <img> generator — paste a Base64 value, choose a language (Python, JavaScript, C#, cURL, or an HTML image tag), set the MIME type if you're making an image tag, and click Generate to get copy-ready code.

10. Folder Watch

Process files automatically as they appear in a folder.

1
Choose Encode or Decode and a Format.
2
Pick the folder to watch and, optionally, a file filter (for example *.bin).
3
Click Start.

From then on, any matching file dropped into that folder is processed automatically, and each action is listed in the log. The app waits until a file has finished copying before it processes it, and it never re-processes the files it produced itself. The format and folder options are locked while watching. Click Stop when you're done.

11. History

A running list of your recent operations (Text, File, Batch and Pipeline), with the time and the sizes involved. It never stores the text you encoded or decoded. It's kept between sessions. Use Clear to empty it (you'll be asked to confirm), or turn it off completely in Settings.

12. Settings

  • Dark theme — toggle the app's appearance. (You can also use the sun/moon button at the bottom of the side panel.)
  • Preserve timestamps & attributes — the default for the File, Batch and Folder Watch sections.
  • Record operations in History — untick to stop recording anything in History.
  • About Base64 Encoder and Decoder — shows the version and app information, with a link to the product website.

Your settings are saved automatically and remembered the next time you open the app.

13. Tips

  • Stuck with a mystery string? Paste it into Text and hit Detect.
  • For very large files, use the File section — it shows progress and can be cancelled.
  • Combine steps you do often into a Pipeline and save time.
  • Drag and drop works in both the File and Batch sections.
  • Decoded something that turned out to be an image or archive? Use Save bytes… in the Text section rather than copying the Output box.
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