Base64 Encoder / Decoder
Encode text or files to Base64, or decode Base64 strings back to plain text. Runs 100% in your browser — nothing is sent to a server.
Plain Text
Base64 Output
Encode text or files to Base64, or decode Base64 strings back to plain text. Runs 100% in your browser — nothing is sent to a server.
Base64 is a binary-to-text encoding scheme that converts binary data into a sequence of printable ASCII characters. It was designed to allow arbitrary binary data to be transmitted safely over text-only channels — such as email (MIME), XML documents, and HTTP headers — that might otherwise corrupt or truncate raw binary content. The name "Base64" comes from the 64 characters used in the encoding alphabet: A–Z, a–z, 0–9, plus (+) and slash (/). Each group of three binary bytes is represented as four Base64 characters, resulting in an encoded size approximately 33% larger than the original.
Base64 encoding is used in a wide variety of real-world scenarios. In web development, it is commonly used to embed small images or fonts directly into CSS or HTML as data URLs, eliminating extra HTTP requests and improving page load performance. Email systems use Base64 to encode attachments so that binary files can travel safely through SMTP servers that only handle text. JSON APIs often encode binary payloads — such as cryptographic signatures, PDFs, or audio clips — in Base64 so they can be embedded inside a JSON string without escaping issues. Authentication tokens, such as JWTs (JSON Web Tokens), use Base64URL encoding for their header and payload sections. Configuration files for cloud platforms like Kubernetes encode secrets in Base64 before storing them in YAML manifests. Understanding when and how to use Base64 encoding is an essential skill for developers, system administrators, and security engineers.
Using the DOLY Studio Base64 Encoder/Decoder is simple and straightforward. To encode plain text: type or paste your text into the left panel, then click the green Encode button. The Base64-encoded result appears immediately in the right panel. To decode Base64: paste a Base64 string into the left panel and click the Decode button to recover the original text. Use the Upload File button to encode any file — images, PDFs, documents — directly to Base64 without leaving the page. The Swap button lets you flip the input and output panels so you can quickly re-encode or re-decode. When you are ready, click Copy to copy the result to your clipboard. All processing is done locally in your browser; no data is transmitted to any server.
Standard Base64 uses the characters + and /, which are reserved characters in URLs. When Base64-encoded data needs to appear in a URL query string or path segment — such as in OAuth tokens, file download links, or cookie values — URL-safe Base64 is used instead. URL-safe Base64 replaces + with - and / with _, and typically omits the padding = characters. This tool supports URL-safe Base64 via the Charset selector in the toolbar. Select "URL-safe Base64" before encoding to get a result that is safe to embed in URLs without percent-encoding.
No data ever leaves your browser. All Base64 encoding and decoding happens entirely client-side using the browser's built-in JavaScript APIs. This means you can safely encode sensitive text, API keys, personal information, or confidential files without any privacy risk. There are no server logs, no cookies tied to your input, and no third-party services involved in the encoding process.
Because the tool runs in your browser, the practical size limit depends on your device's available memory. Most modern browsers handle files up to 10–20 MB without any issues. For very large files (above 50 MB), you may experience slower processing or a brief pause while the browser encodes the binary data. If you need to encode extremely large files, a command-line tool like base64 on Linux/macOS or PowerShell on Windows may be more efficient.
Standard Base64 uses the characters + and / as part of its 64-character alphabet, and pads encoded strings with = to make the length a multiple of four. URL-safe Base64 (defined in RFC 4648) replaces + with - and / with _, and omits or makes padding optional. Use URL-safe Base64 when the encoded string will appear in a URL, filename, cookie, or any other context where +, /, and = have special meaning or need to be percent-encoded.
This usually means the original Base64 string was produced from non-UTF-8 content — such as a binary file, an image, or text encoded in a different character set like Latin-1 or UTF-16. If you are trying to decode a file that was encoded as Base64, you should save the decoded output as a binary file rather than reading it as plain text. If the source text was encoded using a specific character set, select that character set from the Charset selector before decoding.
No. Base64 is an encoding scheme, not an encryption algorithm. It does not protect data from unauthorized access — anyone who has the Base64 string can decode it instantly without a key or password. Base64 simply transforms binary data into a text-safe format for transmission or storage. If you need to protect data, use a proper encryption algorithm such as AES-256 along with a strong secret key. Do not rely on Base64 to hide sensitive information.