Free Base64 Decoder
Paste any Base64-encoded string and get the original text back in one click. Whether you are debugging API responses, inspecting tokens, or recovering data from encoded payloads, this free Base64 decoder handles full UTF-8 — including emoji and non-Latin scripts — validates your input, and works entirely in your browser.
Decoded text
How to Use the Base64 Decode
- Paste your Base64-encoded string into the input box (whitespace and line breaks are ignored).
- Click Decode — the original text appears instantly below.
- Use Copy to copy the result or Download to save it as a .txt file.
- If the input is malformed you will get a clear error explaining what is wrong.
Features
This decoder accepts both standard Base64 and the URL-safe variant (with - and _), automatically strips whitespace and line breaks copied from formatted documents, and decodes bytes through a strict UTF-8 decoder so multilingual text and emoji survive intact. Invalid input is rejected with a specific message — bad characters, wrong padding, or truncated data — instead of silent garbage output.
Benefits & Use Cases
Backend developers paste opaque tokens and data URIs here to see what is actually inside them; frontend developers decode embedded assets and API payloads during debugging. Because everything runs locally, you can safely inspect sensitive strings — session tokens, internal IDs, encoded credentials — without sending them to a third-party server.
Tips
If decoding fails, look for missing = padding at the end of the string — Base64 length must be a multiple of 4. When copying from PDFs or chat apps, stray spaces sometimes sneak in; this tool ignores them automatically. For JWTs, decode the middle segment (between the two dots) to read the payload.
Frequently Asked Questions
What is Base64 decoding?
Base64 decoding reverses Base64 encoding: it converts text made of A-Z, a-z, 0-9, + and / back into the original bytes or text. Developers use it to inspect tokens, data URIs, email attachments, and API payloads.
Does this decoder handle Unicode and emoji correctly?
Yes. Many online decoders corrupt non-ASCII characters because they skip the UTF-8 step. This tool decodes the raw bytes with a strict UTF-8 decoder, so emoji, accented letters, and CJK characters come back exactly as encoded.
Is my data sent to a server?
No. Decoding happens locally in your browser with JavaScript. Nothing you paste is uploaded, logged, or stored anywhere.
What does an invalid Base64 error mean?
It means the input contains characters outside the Base64 alphabet, has incorrect = padding, or its length is not a multiple of 4. Check for truncated strings or characters mangled by rich-text editors.
Can I decode URL-safe Base64?
Yes. The decoder accepts the URL-safe variant that uses - and _ instead of + and /, which is common in JWTs and web tokens, and converts it automatically.
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