Free Base64 Encoder & Decoder
Runs locallyUpdated October 25, 2026
Encode UTF-8 text strings into RFC 4648 Base64 or decode Base64 payloads locally in your browser without sending data to a server.
How to use Base64 Encoder / Decoder
Paste your plain UTF-8 text or a Base64-encoded string into the input box.
Select Encode to convert text into Base64 (A–Z, a–z, 0–9, +, /, =) or Decode to restore the original UTF-8 text.
Copy the output for use in HTTP Basic Auth headers, data URIs, or API payloads.
Encode and decode UTF-8 Base64 strings locally in your browser
When debugging HTTP Basic Authentication headers, inspecting JWT payload segments, or decoding API fields, pasting private strings into server-side web tools is a security risk. This free Base64 encoder and decoder processes UTF-8 strings entirely inside your browser memory.
Base64 quick reference & examples
| Input Text (UTF-8) | Base64 Encoded Output | Notes |
|---|---|---|
user:password123 | dXNlcjpwYXNzd29yZDEyMw== | Standard format used inside Authorization: Basic <base64> headers |
{"alg":"HS256","typ":"JWT"} | eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9 | Typical JSON header segment (starts with eyJ, which is {" in Base64) |
NitroSERP 2026 | Tml0cm9TRVJQIDIwMjY= | 14-byte ASCII string padded with a single = |
Related developer & encoding tools
After decoding a Base64 JSON payload, paste the result into our JSON formatter & validator to pretty-print it. Need percent-encoding for URLs instead of Base64? Open the URL encoder / decoder or HTML entities encoder / decoder.
Base64 Encoder / Decoder FAQs
A–Z, a–z, 0–9, +, /, and = padding) so data can travel safely inside JSON payloads, HTML data: URIs, email MIME bodies, and HTTP Authorization: Basic headers.Related Code & Developer Tools
More code & developer tools and nearby utilities.
HTML Minifier / Beautifier
Collapse whitespace to minify HTML snippets or pretty-print nested markup locally in your browser with no server uploads.
Open tool →HTML Entities Encoder / Decoder
Escape reserved HTML characters (<, >, &, ", ') into safe character entities or decode escaped markup locally in your browser.
Open tool →MD5 Hash Generator
Compute 128-bit (32-character hexadecimal) MD5 checksum digests locally in your browser for non-cryptographic deduplication and legacy integrations.
Open tool →SHA-256 Hash Generator
Compute 256-bit (64-character hexadecimal) SHA-256 cryptographic hashes locally in your browser using the native Web Crypto API (crypto.subtle.digest).
Open tool →