Base64 Encode/Decode
Encode text, files, and binary values with the requested alphabet.
Runs in your browser. Nothing is uploaded.
Standard and URL-safe Base64
Standard Base64 uses + and / with padding. URL-safe Base64 uses - and _ and accepts missing padding, so choose the alphabet your receiving system expects.
Base64 is an encoding, not encryption
Base64 changes bytes into printable characters so systems can move data through text-oriented fields. It does not hide the data and it does not prove who created it. Anyone with the encoded value can decode it. Do not use Base64 as a password format, access control, or replacement for encryption. If a value must be confidential, use an encryption design with key management.
Text input is converted as UTF-8. Accented characters, symbols, and non-Latin scripts are first represented as UTF-8 bytes, then encoded. Dropped files are encoded from their original bytes, and decoding can download binary output. If another system expects a legacy character set or raw binary, confirm its contract before treating the result as interchangeable.
Padding and URL-safe values
Standard Base64 uses an alphabet with 64 characters. It uses + and /, and adds one or two = characters when the input does not fill a complete group of three bytes. URL-safe Base64 replaces + with - and / with _. Some token formats omit the padding, so use the mode your receiving system documents instead of switching based on appearance.
JWT segments use Base64url for their header and payload. A JWT is still not encrypted just because those segments look unfamiliar. Use the JWT Decoder to inspect a token locally, and keep the signature and verification distinction clear.
Check what the receiving system expects
Base64 output is longer than the original bytes, often by about one third. It is useful for transport, fixtures, and small text values, but it is not a compression format. Watch for whitespace added by copied values and for systems that require or reject padding. The tool runs in your browser and reports invalid input instead of sending it elsewhere.
FAQ
Can I encode a local file without uploading it?
When you drop a file, its bytes are encoded in your browser. The bytes are never uploaded, and TheDevTab never receives them.
What is standard Base64?
Standard Base64 uses A-Z, a-z, 0-9, plus (+), and slash (/), with equals signs for required padding. Choose it when the receiving system expects the standard alphabet.
What is URL-safe Base64?
URL-safe Base64 replaces plus with a hyphen and slash with an underscore, then removes trailing padding when it encodes. Its decoder accepts an unpadded value or correctly sized optional padding.
Does Base64 encrypt text?
No. Base64 changes bytes into printable text but provides no confidentiality or access control. Anyone with the encoded value can decode it, so it is not protection for secrets.
How does Base64 handle non-ASCII text?
Text input is converted to UTF-8 bytes before encoding, so accented characters and non-Latin scripts can roundtrip. Text decoding uses a fatal UTF-8 decoder and reports an error when the bytes are not valid UTF-8.
What does the Data URL option produce?
When encoding, Data URL prefixes the result with data:application/octet-stream;base64,. Decoding also recognizes and removes a data URL prefix before validating the Base64 payload.