Base64 Decoder

You convert Base64-encoded data into readable text by reversing the 6-bit mapping that translates binary streams into a restricted ASCII alphabet. This representation prevents corruption when email gateways, database fields, or URL parameters cannot accept raw bytes. Decoding restores the original bytes so you can inspect, search, or reuse them in other applications.

Inside this utility, a lightweight reactive engine decodes every character entirely on your device. Optional switches correct URL-safe variants, append missing padding, or strip stray whitespace before a typed decoder translates the byte array back to Unicode. No network request is needed, preserving confidentiality even when you analyse sensitive certificates or authentication tokens.

Use this decoder when you need to inspect webhook payloads, recover obfuscated images, or verify email attachments without leaving the browser, because it translates the encoded text immediately and presents previews for supported media while keeping files on your device; scan any downloaded binary with trusted security software before opening.

Technical Details:

The interface binds form inputs to a lightweight client-side decoder that transforms the Base64 string into a byte array, converts it with a text decoder, and displays size statistics instantly. A sandboxed object URL renders image, audio, or video previews while clipboard and download APIs streamline export.

Offline decoding engine

Processes every character inside the browser’s memory; nothing leaves the session.

URL-safe conversion

Replaces “-” and “_” with “+” and “/” to handle web-friendly inputs transparently.

Whitespace trimming

Optionally strips line breaks or spaces that often appear in email or JWT payloads.

History ledger

Stores the ten most recent decodes in local storage for quick recall and reuse.

Media preview & export

Detects MIME types, renders previews, and enables one-click copy or download.

Step-by-Step Guide:

1. Paste your string into the Base64 Data textarea or drop a file.
2. Toggle URL-safe, No padding, or Strip whitespace as required.
3. Click Advanced to enable Copy automatically or Wrap long lines.
4. Read the Decoded Text area; use the Copy or Download buttons for export.
5. Select History to reopen previous outputs or Clear History to purge local data.

FAQ:

Troubleshooting:

• Decoder shows blank result — Check for unintended whitespace or non-ASCII symbols.
• “Invalid character” error — Enable URL-safe toggle or strip whitespace.
• Copy button does nothing — Ensure clipboard permissions are allowed in browser settings.
• Preview missing — The MIME type may not be an image, audio, or video.
• Download fails — Pop-up blockers can block the anchor click; allow the site temporarily.

Advanced Tips:

• Press Ctrl + Enter to copy decoded text instantly.
• Use ?input= query parameter to preload the page with encoded data.
• Drag any Base64-encoded .txt file onto the textarea for batch work.
• Disable line wrap to preserve original formatting when inspecting certificates.
• Shift-click History items to append instead of replace.

Glossary:

Base64

Encoding that maps binary data to 64 ASCII characters.

Padding

“=” symbols appended to complete 4-character blocks.

URL-safe

Variant replacing “+ /” with “- _” for safe URLs.

Local storage

Browser key-value store persisting data per domain.

MIME

Standard identifier describing data type, e.g., image/png.