Base64 encoder and decoder online — encode text privately
Base64 encodes binary data as ASCII text — common in Basic Auth headers, data URIs, email, JWT segments, and config snippets. Our Base64 encoder and decoder online runs in your browser: paste plain text to encode, or paste Base64 to decode back, with Unicode-aware handling.
No account, no server upload, no limits. Switch between Encode and Decode modes, copy results in one click, and clear the panel when finished. Ideal when you need a quick base64 encode online or base64 decode online without installing openssl or scripting in Python.
What this Base64 converter does
Encode mode turns UTF-8 text into a Base64 string using standard btoa-compatible logic with Unicode support. Decode mode reverses Base64 to readable text and surfaces clear errors for invalid padding or characters. Split layout: input and output side by side. Copy and Clear match the rest of Mini Tooly.
How to encode and decode Base64 (step by step)
Step 1 — Choose Encode to convert text to Base64, or Decode to reverse a string. Step 2 — Paste or type in the input area. Step 3 — Read the result panel; fix invalid Base64 if decoding fails (check padding = and URL-safe variants). Step 4 — Copy the output into your header, .env, JSON field, or HTML data URI. Step 5 — Clear when working with secrets on a shared computer.
Who uses a Base64 encoder decoder
Backend developers build Authorization: Basic headers. Frontend devs craft data:image/png;base64 URIs. DevOps decode secrets from CI logs (carefully). Students learn encoding in security courses. QA verify API payloads that embed Base64 fields.
Common Base64 use cases
Basic Auth: username:password encoded for HTTP headers. Data URIs: embed small icons in CSS or HTML without extra requests. JSON APIs: fields that carry binary as Base64 strings. Note: Base64 is not encryption — never treat it as secure storage for passwords.
Why use this online Base64 tool
Runs locally — credentials are not sent to our servers. Unicode-safe encode and decode for international text. Free and instant. Pairs with JSON Formatter for payloads that mix JSON and Base64, and Image to WebP when you later replace data URIs with real image files.
Frequently asked questions
Is Base64 encryption? No — it is encoding anyone can reverse. Is this tool free? Yes. Is my text uploaded? No — processing is client-side. Why does decode fail? Invalid characters, wrong padding, or truncated paste — ensure standard Base64 alphabet. Does it support Unicode? Yes — encode and decode handle UTF-8 text.
Related tools
Validate JSON payloads with JSON Formatter (/json-formatter). Shrink images with Image to WebP (/image-to-webp). Build CSS in the playground (/css-shadow-generator). Browse all tools (/).