● Encoding
Base64 Decoder
Decode Base64 encoded strings back into UTF-8 plain text.
Processed locally. Your input stays in this browser.
Zero Data Sent1 line•52 chars•52 B
Ctrl/Cmd+Enter run
Decoded Plain Text Output
1 line•36 chars•38 B
Read-only output
What Base64 Decoder Does
Decode Base64 strings to readable UTF-8 text with strict error reporting.
How It Works
- 1.Paste a Base64 encoded string into the input editor.
- 2.The decoder parses atob bytes and converts UTF-8 sequences safely using TextDecoder.
- 3.View or copy the decoded plain text.
Common Use Cases
- •Decoding Basic Auth headers (username:password).
- •Inspecting encoded payload data in HTTP requests or logs.
Related Developer Guides
How to Decode & Inspect JWT Tokens Safely
Comprehensive guide to JSON Web Tokens (JWT). Learn how to decode JWT headers and payloads, check token expiration (exp), inspect claim scopes, and verify signatures.
Read GuideBase64 Encoding Explained: How Binary-to-Text Encoding Works
Deep dive into Base64 encoding. Understand 6-bit binary translation, Base64 character index tables, padding with =, URL-safe Base64, and UTF-8 string encoding.
Read GuideFrequently Asked Questions
What happens if the input is invalid?
The decoder will display a clear error message indicating invalid characters or malformed padding.