Free online tool
Free Online Base64 Encoder / Decoder
Encode and decode base64 online. Supports standard base64 and URL-safe variant (used in JWTs and URL parameters). UTF-8 aware — handles emoji, accents, and non-Latin scripts. Live two-way transform. 100% client-side.
01How it works
Type or paste text
Enter plain text on the left. The base64 encoded version appears on the right instantly.
Or paste base64
Paste base64 on the right side. The decoded plain text appears on the left instantly.
Toggle URL-safe if needed
Enable URL-safe mode for tokens and URL parameters. Both sides update to reflect the selected variant.
FAQ
Frequently asked questions
What is the URL-safe base64 variant and when do I need it?
URL-safe base64 replaces + with - and / with _ and drops the = padding characters. This variant is used in JWTs, OAuth tokens, and anywhere a base64 string appears inside a URL or header, because + and / have special meanings in URLs and would need percent-encoding otherwise.
How are non-ASCII characters (emoji, accents) handled?
The encoder routes all text through TextEncoder (UTF-8) before base64-encoding, and the decoder routes the decoded bytes through TextDecoder (UTF-8) on the way back. This means emoji, accented characters, and CJK text all round-trip correctly. Raw binary data (non-UTF-8 bytes) is not supported — use a file download tool for that.
What does the = padding at the end of base64 mean?
Standard base64 uses = characters to pad the output to a multiple of 4 characters. URL-safe base64 omits the padding because the = character has meaning in URL query strings. Both variants are accepted on the decode side — the decoder re-adds padding as needed.
How does the live two-way editing work?
Edit either the plain text or the base64 side. When you type in the plain pane, the base64 pane updates immediately. When you type in the base64 pane, the plain pane updates immediately. If the base64 is malformed, an error message appears between the two panes.
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