Base64 Encoder/Decoder
Free online Base64 converter — encode and decode text, supports UTF-8, files, and Base64URL. No registration.
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Free online Base64 converter — encode and decode text, supports UTF-8, files, and Base64URL. No registration.
Base64 is a binary-to-text encoding scheme that represents binary data using 64 ASCII characters (A–Z, a–z, 0–9, +, /). It is widely used in web development to transmit binary data through text-based formats — embedding images in HTML/CSS as data URIs, sending file attachments in REST APIs, or storing JWT tokens. itcoders.pl Base64 Encoder/Decoder runs entirely in the browser: no data leaves your device.
Paste text for encoding or a Base64 string for decoding in the left panel. The tool automatically detects the correct mode — if the input looks like Base64, it switches to decoding. You can also manually select the mode with the Encode or Decode buttons. The Swap button instantly exchanges data between panels. The result can be copied to the clipboard or downloaded as a text file.
Base64URL mode replaces + and / with - and _, also removing = characters — this variant is safe for URLs and file names. Wrapping every 76 characters (MIME standard) is useful when embedding Base64 in email bodies or headers. The file upload feature converts any file (image, PDF, ZIP) into a Base64 representation — handy when sending files through JSON APIs. Decoding a file back works automatically: if the result is not readable text, the tool offers a file download.
All encoding and decoding happens client-side — no fragment of pasted text or uploaded file is sent to a server. This makes it safe for working with JWT tokens, API keys, certificates or sensitive data. itcoders.pl Base64 Encoder/Decoder is fully free, requires no registration and works in any modern browser.
No — Base64 is encoding, not encryption. Anyone can decode Base64 without a key. It only converts binary data to a text format. For data protection, use encryption (AES, RSA, etc.) and use Base64 only as a transport layer.
Base64 encodes 3 bytes of binary data as 4 text characters, which increases size by approximately 33%. This is the trade-off for being able to transmit binary data through text formats like JSON, HTML or HTTP headers.
Standard Base64 uses + and / characters, which have special meaning in URLs. Base64URL replaces them with - and _, and removes = padding — making the output safe to use in URLs and file names without percent-encoding.
Yes — the tool uses UTF-8 encoding which supports all Unicode characters, including accented letters, Cyrillic, Chinese characters and emoji. Unlike the standard btoa() function, which throws an error on non-ASCII characters.