Decoding the encoded sample returns Hello from Kampala 👋 with the emoji intact.
DATA & TEXT · FREE JAVASCRIPT TOOL
JavaScript Base64 Encoder & Decoder
Encode Unicode text to Base64 or decode Base64 back into readable UTF-8 text.
Free to useNo sign-upRuns in your browser
JS
JS Base64 ToolLocal browser processing
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Your processed result will appear here.
A WORKED TASK
Round-trip a greeting containing an emoji
Encode the sample greeting, copy the result into the input and switch to Decode Base64. The tool converts text to UTF-8 bytes before Base64 encoding, which allows the emoji to survive the round trip. Direct btoa on arbitrary Unicode is not an equivalent workflow.
Base64 makes bytes representable as text. It does not conceal a secret, compress a file or upload content to a public address. This decoder returns UTF-8 text rather than arbitrary binary downloads.
What to check
- Use raw Base64 text, without a data: URL prefix.
- Invalid Base64 syntax and decoded bytes that are not valid UTF-8 are different errors.
- JWT segments use Base64URL conventions; use the JWT decoder for that format.
TESTED & REVIEWED
Know what this tool does—and where to double-check
- Reviewed by
- HTML Online Viewer project
- Last reviewed
- Processing
- Ordinary processing happens in this browser tab; the tool does not intentionally upload your source.
- Important limitation
- JavaScript checks and transformations cannot prove that application logic is correct. Test the result in its real project before publishing.
PRACTICAL EXAMPLE
Start with a small JS Base64 Tool example
The built-in sample makes the accepted input visible before you use your own project data.Example input
Loaded in the workspace
Hello from Kampala 👋Run the sample first, then change one value at a time so each result remains easy to explain.
What this example demonstrates
Encode Unicode text to Base64 or decode Base64 back into readable UTF-8 text.
Keep the original file, review the generated result and test production code in its real application before publishing.
COMMON QUESTIONS
JS Base64 Tool FAQ
Is JS Base64 Tool free?
Yes. It is free to use and requires no account.
Does JS Base64 Tool upload my source?
No. Ordinary processing happens locally in the current browser. The JavaScript runner uses a short-lived isolated browser worker.
Can I import and export a file with JS Base64 Tool?
Yes. Import a relevant JavaScript, JSON or text file, then save the input or processed result.