Base64 encoder & decoder (UTF-8)
Turn plain text into Base64, or recover text from a Base64 string — with correct Unicode / UTF-8 handling (not raw btoa/atob on international characters). Optionally load a small file (encode binary to Base64, or decode a file whose contents are Base64 text). Everything runs in your browser; nothing is uploaded to our servers.
Tip: Ctrl+Enter (Windows) or Cmd+Enter (Mac) runs encode. Whitespace in Base64 is ignored when decoding.
Tip: Ctrl+Enter runs decode. Padding = may be omitted; invalid characters show a clear error.
When a file is selected, Run uses the file, not the text box.
Very large pastes may slow your browser; prefer files under 2 MB or a local script for huge binaries.
Automate this. CloudyBot can move data between APIs, files, and chat on a schedule — encode or decode inside workflows instead of manual copy-paste.
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How it works
Base64 represents binary data as ASCII text using 64 safe characters. It is everywhere: email attachments (MIME), JSON web tokens (after the dot-separated segments are separately encoded), data URLs, and quick binary-to-text copy-paste in tickets or chat.
Web APIs btoa and atob assume each character is a single byte in the Latin-1 range. Real-world text is usually UTF-8, where emoji and non-English letters span multiple bytes. This tool encodes by converting your string to UTF-8 bytes first, then applying Base64. Decoding reverses that: Base64 → bytes → UTF-8 text. If decoded bytes are not valid UTF-8 (for example, binary payloads), you will see an error suggesting a different workflow.
Files: In encode mode, a file is read as raw bytes and converted to a Base64 string (typical for embedding or transport). In decode mode, the file is read as text; its contents are treated as Base64 and decoded to UTF-8 — useful when you have exported Base64 in a .txt file.
Common use cases
- Debug API payloads that wrap UTF-8 JSON or protobuf in Base64.
- Prepare data URLs or snippets for HTML, CSS, or documentation.
- Compare environments — encode the same Unicode string and verify identical Base64 across systems.
- Learn JWT structure — pair with our JWT decoder after you understand raw segments.
- Quick checks before scripting the same transform in Node, Python, or Bash.
Want Base64 inside scheduled workflows?
Example: “Every hour, fetch an endpoint, Base64-decode a field, and alert me if the JSON inside changes.” CloudyBot runs in the cloud with memory and optional cron-style schedules — so you are not tied to this page for repetitive work.
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Base64 decoder and encoder in one place
People search for a Base64 decoder, Base64 encoder, or online Base64 when they need to inspect or produce ASCII-safe blobs without installing software. This page focuses on UTF-8 text correctness and privacy (client-side processing). If you are comparing tools, check whether they mangle Unicode — many simple snippets do. For recurring automation, CloudyBot can handle transforms and API calls so you are not pasting into a browser tab every time.
When Base64 is the wrong tool
Base64 is not encryption. Anyone can decode it instantly. Do not use it to hide API keys, passwords, or personal data. For secrets you need real cryptography (TLS in transit, vaults at rest) and tight access control.
Base64 also does not compress — it typically grows size by roughly a third. If the goal is smaller payloads, use gzip, Brotli, or protocol-level compression instead of encoding raw binary as Base64 and hoping for savings.
For structured text inside tokens, pair this page with the JWT decoder (segments are Base64url) and the JSON formatter once you decode embedded UTF-8 JSON.
Frequently asked questions
Is this Base64 tool free?
Yes. There is no signup and no usage limit for this page. Encode and decode as often as you like.
Is my text or file sent to CloudyBot servers?
No. Encoding and decoding run entirely in your browser using JavaScript. Open DevTools Network and you will not see your paste or file contents sent to our origin for these actions.
Why not use btoa and atob directly for Unicode?
Browser atob and btoa treat strings as Latin-1 bytes, which mangles characters outside ASCII. This tool converts text to UTF-8 bytes first, then Base64, and reverses that when decoding so emoji and international text work correctly.
What is the file size limit?
Files are read in the browser up to 2 MB per load. Larger files should be processed with local command-line tools or scripts to avoid freezing the tab.
Can I use this free Base64 tool for API keys or secrets?
Technically yes — encode and decode still run only in your tab. Follow your org’s policy: avoid pasting production secrets on shared computers, and prefer a secrets manager or environment variables for real credentials.
Why does decoding fail with not valid UTF-8?
The Base64 might decode to arbitrary binary (images, compressed data, or encrypted bytes). This tool interprets the result as UTF-8 text. For binary outputs, use a hex viewer or a script that writes bytes to a file.
What is CloudyBot?
CloudyBot is a hosted AI agent that can browse the web, use files, remember context, and run tasks on a schedule. This Base64 page is a free utility; the product automates workflows so you are not manually encoding payloads forever.
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