Base64 encoder & decoder
Encode and decode Base64 or Base64URL, including UTF-8 text and binary data.
Processed locally · No input or result uploaded
How to encode and decode Base64
Choose Encode or Decode, select Standard Base64 or Base64URL, paste your value. The result updates automatically. Copy the result or download its original bytes. Whitespace is preserved when encoding.
What is Base64?
Base64 represents binary bytes using a text alphabet. It is commonly used in HTTP authentication, JWTs and webhook payloads. It is encoding, not encryption.
Examples
Hello ↔ SGVsbG8=
Unicode text: Zażółć gęślą jaźń
Authorization: Basic dXNlcjpwYXNzd29yZA== ↔ user:password
Basic authentication requires HTTPS. Decoding JWT segments does not verify signatures.
{"event":"document.created","document":{"content":"SGVsbG8="}}Frequently asked questions
Is this tool free?
Yes. Encode and decode without an account or subscription.
Is my data uploaded?
Conversion runs in page and worker memory in your browser. No conversion data is uploaded or saved by this tool. Refreshing or leaving clears the editor; your operating system clipboard remains under your control.
Does it support Unicode?
Yes. Text is encoded as UTF-8, including Polish characters, emoji and other Unicode scripts. A lone UTF-16 surrogate is replaced with U+FFFD and produces a warning.
What is the difference between Base64 and Base64URL?
Standard Base64 uses + and /. Base64URL uses - and _ for URL-safe values. Standard encoding includes padding by default; Base64URL omits it by default. Choose the matching alphabet before decoding.
Can I decode without padding?
Yes, when Accept missing padding is enabled. Completely absent padding is accepted, but partial or misplaced padding is rejected. Unused pad bits must be zero in either case.
Why does decoding fail?
Check the selected alphabet, invalid characters, length and padding. Only ASCII spaces, tabs, CR and LF can be ignored. Mixed alphabets and non-canonical pad bits are rejected.
Is Base64 encryption?
No. Base64 is a reversible representation of bytes, with no confidentiality. Basic authentication needs secure transport (HTTPS). Decoding a JWT does not verify its signature or prove its claims are trustworthy.
Can I decode binary data?
Yes. Invalid UTF-8 is a successful binary decode. Inspect the first 256 bytes in HEX and download all original bytes as decoded.bin. Binary output cannot be copied as text.
See what your webhooks send
Create a receiving URL, inspect request bodies and headers privately, and control the HTTP response. Start debugging without an account.