Base64 Decoder — Decode Base64 Strings to Text Online

Paste any Base64 string and see the decoded text instantly. Automatically handles URL-safe encoding, MIME line breaks, and missing padding.

Common Decoding Scenarios

Developers frequently need to decode Base64 when debugging API responses that contain encoded payloads, inspecting JWT tokens (the header and payload are Base64url-encoded JSON), reading HTTP Basic Auth headers, extracting data from email MIME attachments, or examining webhook payloads from services like GitHub, Stripe, or AWS.

Handling Decoding Errors

The most common Base64 decoding errors come from URL-safe encoding (uses - and _ instead of + and /), missing padding (some encoders strip trailing = characters), and embedded whitespace (MIME-encoded data has line breaks every 76 characters). This tool handles all these cases automatically — toggle URL-safe mode if standard decoding fails, and whitespace is always stripped before decoding.

Decoding JWT Tokens

JSON Formatter.

Paste your Base64 string below — the decoder is already active.

Base64 Input0 B
Decoded Text
Decoded text will appear here...