Base64 decoder

Free Base64 Decoder Tool

The Free Base64 Decoder tool converts Base64-encoded strings back into readable text, binary files, or images. It saves time by instantly revealing the original content for debugging, data recovery, and integration tasks. Use the Base64 Decoder whenever you need to decode Base64 from APIs, emails, data URLs, or configuration files.

What is Base64 Decoder?

The Base64 Decoder is a utility that transforms Base64-encoded data into its original form—plain text, JSON, binary files, or images. Base64 encoding is commonly used to transmit binary data over text-based channels like JSON, HTML, and email. A reliable Base64 Decoder lets you quickly inspect and extract that original content.

On Monkey Type, this Base64 Decoder simplifies troubleshooting and development workflows. Paste a Base64 string and instantly view the decoded output, preview images, or download binary files. Whether you are reversing a data URI or checking the contents of an email attachment, the tool provides fast and accurate results.

If you also need to generate Base64 for uploads or inline assets, try our complementary Base64 Encoder to encode text or files.

Why Use Base64 Decoder?

• Debug APIs and webhooks: When an API returns Base64-encoded payloads, the Base64 Decoder reveals the original JSON or file so you can validate fields and fix integration issues. For structured output, format the result with the JSON Formatter.
• Recover email attachments and MIME parts: Many mail systems store attachments in Base64. Decode them to retrieve PDFs, images, or logs and download clean files.
• Unpack data URIs: Websites often embed images as data URLs. Use the Base64 Decoder to extract and save the underlying PNG, JPG, SVG, or GIF.
• Inspect tokens and configuration values: Some secrets or tokens include Base64 segments. Decode to verify contents for debugging. For token payloads, the JWT Decoder is also helpful.
• Fix encoding issues fast: If text looks garbled, quickly test different character sets to recover readable content and keep your project moving.

How to Use Base64 Decoder on Monkey Type

1. Paste or upload: Insert your Base64 string into the input box. You can also upload a .b64 or text file containing encoded data.
2. Auto-detect or set options: The Base64 Decoder auto-detects common data URI prefixes like data:image/png;base64,. Optionally select text encoding (e.g., UTF-8) or choose “Output as file.”
3. Click Decode: The tool converts Base64 to its original form. For text, you’ll see readable output. For images and binaries, you’ll get a preview and a download button.
4. Copy or download: Copy decoded text, preview images, or download the reconstructed file with one click.
5. Troubleshoot: If decoding fails, check for missing padding (=) or URL-escaped characters. For URL-escaped input, use the URL Encoder/Decoder first, then decode Base64.

Expected result: Clean, readable text or a valid file that matches the original data before it was Base64-encoded.

Key Features

• Instant decoding: Real-time Base64 to text/file conversion with immediate preview for images.
• Data URI support: Automatically strips prefixes like data:application/pdf;base64, before decoding.
• Text and binary output: Decode to readable text (UTF-8 and more) or reconstruct exact binary files.
• Error handling: Helpful messages for invalid characters, incorrect padding, or truncated input.
• Whitespace tolerant: Safely ignores newlines and spaces often introduced by email clients or logs.
• Client-side processing: The Base64 Decoder runs in your browser for speed and privacy.
• Handy integrations: Pipe decoded JSON into the JSON Formatter for clean, indented output.

Best Practices & Tips

• Remove prefixes: If your string starts with data:...;base64,, strip it or let the Base64 Decoder auto-detect and remove it for cleaner results.
• Fix URL encoding first: Base64 in URLs may contain %2B or %2F. Use the URL Encoder/Decoder to unescape before decoding.
• Check padding: Ensure proper = or == padding at the end of the Base64 string; missing padding causes “invalid length” errors.
• Select the right charset: If decoded text shows strange characters, try a different encoding (e.g., ISO-8859-1) to recover original text.
• Validate output: For JSON content, verify structure using the JSON Formatter to catch hidden errors fast.
• Keep security in mind: Avoid executing decoded scripts and always inspect content before use.

Common Use Cases

• API debugging: Decode Base64-encoded fields returned by services to validate payloads and logs.
• Email forensics: Convert Base64 MIME parts to recover attachments or inline images.
• Web development: Extract images from data URIs for optimization or asset management.
• Token inspection: Decode Base64 segments inside tokens or configs to verify contents; for full token parsing, try the JWT Decoder.
• Backup and restore: Turn Base64-encoded archives or files back into their original formats for testing or recovery.

Frequently Asked Questions

What does the Base64 Decoder do?

The Base64 Decoder converts Base64-encoded strings back to their original text or binary form. Use it to recover JSON, files, or images that were encoded for safe transmission over text-only channels.

Is using the Base64 Decoder on Monkey Type secure?

Yes. The Base64 Decoder processes data in your browser, so your content is not uploaded to a server. This client-side approach improves privacy and performance on Monkey Type.

Why is my decoded text unreadable?

Garbled text usually indicates a character set mismatch or URL-escaped input. Try changing the output encoding or first unescape with the URL Encoder/Decoder, then run the Base64 Decoder again.

Can the Base64 Decoder handle images and files?

Absolutely. The Base64 Decoder can reconstruct images (PNG, JPG, SVG, GIF) and other binary files, providing previews and download options when possible.

How do I encode data back to Base64?

Use the Base64 Encoder to convert text or files into Base64 for embedding in HTML, JSON, or emails.