What is Base64 encoding?

Base64 encoding turns data into a text-safe string using a 64-character alphabet (A–Z, a–z, 0–9, +, /) plus optional '=' padding. It’s used to transport data through systems that expect text.

Is Base64 encryption? Is it secure?

No. Base64 is not encryption—it's just encoding. Anyone can decode it. Never use Base64 alone to protect secrets, tokens, or personal data.

Why does Base64 increase size by ~33%?

Base64 represents 3 bytes using 4 characters, which adds overhead. The tradeoff is that the result is safe to transmit as plain text.

What’s the difference between Base64 and Base64URL?

Base64URL swaps '+' and '/' for '-' and '_' so it can be safely used in URLs and JWTs without escaping. Use Base64URL for tokens, URLs, and web-safe contexts.

What is Base64 padding (=) and do I need it?

Padding '=' is added so the output length is a multiple of 4. Many decoders expect it (especially older or strict ones). Some systems omit padding (common in Base64URL).

How do I Base64 encode a string in JavaScript?

In browsers you can use btoa for ASCII-only data. For UTF-8/Unicode, use TextEncoder + base64 conversion. This tool handles UTF-8 safely for you.

How do I Base64 encode in Node.js?

Use Buffer.from(text, 'utf8').toString('base64'). This tool is handy when you want a quick UI and copy/paste output.

Can I Base64 encode JSON?

Yes. Encode the JSON string (e.g., '{"a":1}') to Base64. It’s common for passing structured values through env vars or text fields.

Why does my decoded text look broken or like � characters?

That usually happens when the encoder/decoder disagrees on character encoding. Use UTF-8 consistently (this tool encodes as UTF-8 by default).

When should I NOT use Base64?

Avoid Base64 for large files (size overhead) or for security. If you need secrecy, use encryption (AES/GCM etc.) and only then Base64 the ciphertext for transport if needed.

Base64 Encode

Encode text to Base64 instantly (UTF-8). Create Base64 strings for APIs, configs, Basic Auth, and safe text transport — locally in your browser.

Text (Plain)

Auto-detect: paste text to encode

Input

Mode

Encoding

Base64 (Encoded)

Spacer

Output

What is Base64 Encode?

Base64 Encode converts text into Base64 (a text-safe representation of binary data). It’s commonly used when you need to pass data through systems that expect plain text only—like HTTP headers, JSON payloads, query parameters, environment variables, email bodies, or configuration files. This tool encodes using UTF-8 by default, so Unicode characters (emoji, Hebrew/Arabic, accented letters) are preserved correctly. It’s ideal for developer workflows: quickly create Base64 strings for Basic Auth, embed small assets as data, or debug encoded payloads. Everything runs locally in your browser—no uploads and no server processing.

How to Use

Paste or type the text you want to encode (plain text, JSON, XML, etc.)

The tool encodes automatically to Base64 using UTF-8

Copy the Base64 output for use in headers, configs, or API payloads

If you need URL-safe output, use the Base64URL tool (or enable URL-safe mode if available)

If another system expects padding, keep '=' padding enabled (default)

Common Use Cases

Create HTTP Basic Auth credentials (base64(username:password))

Encode JSON snippets or config values for environment variables

Send binary-ish data through text-only channels (headers, JSON, logs)

Generate Base64 for small data URIs or inline payloads in demos

Debug API requests/responses that include Base64 fields

Safely transport Unicode text through systems that mishandle non-ASCII

Prepare test fixtures for unit tests that require Base64 inputs

Key Features

UTF-8 Base64 encoding

Preserves Unicode characters correctly

Standard Base64 output

Compatible with most APIs and libraries

Padding support

Keeps '=' padding for strict decoders (default)

Fast, local processing

Runs in your browser (no uploads)

Copy-ready output

Great for headers, env vars, and payloads

Auto-detect UX

Helps switch between encode/decode flows quickly

Practical examples

Common developer scenarios included

Learn more about this tool with our in-depth guides

Jan 6, 2025•8 min read

Base64 Encoding and Decoding: Complete Developer Guide

Master Base64 encoding and decoding with practical examples. Learn when to use it, common pitfalls, and best practices for handling binary data.

#base64 #encoding #data-conversion+2

Quick Examples

Try these to get started

Encode simple text

Convert plain ASCII text to Base64.

Hello, World!

Encode Unicode text (UTF-8)

UTF-8 encoding preserves Unicode characters (Hebrew, emoji, accents).

שלום 👋 — café

Encode JSON for a config/env var

Encode JSON strings for safe transport in environment variables or text-only systems.

{"env":"prod","featureFlags":{"newUI":true},"region":"eu-west-1"}

HTTP Basic Auth credentials

Encode 'username:password' for Basic Auth (you’ll prepend 'Basic ' to the result in the header).

username:password

Encode a JWT-like JSON claims payload (for testing)

Useful for tests/demos where systems expect Base64 strings (not a real JWT signature).

{"sub":"user_123","scope":"read:users write:users","iat":1700000000}

Encode a multiline value (cert/key snippet example)

Base64 can help store multiline values as a single-line string in env vars/configs.

-----BEGIN KEY-----
line1
line2
-----END KEY-----

Encode a URL-safe-ish payload (use Base64URL for real URLs)

Base64 helps bundle complex strings, but prefer Base64URL when putting it in URLs.

{"redirect":"https://example.com/callback?x=1&y=2"}

Encode XML / SOAP payload fragment

Encode non-JSON text formats for safe transport.

<user><id>123</id><role>admin</role></user>

Common Questions

Find answers quickly

Related Tools

You might also need

Base64 Encoder / Decoder

Encode to Base64 or decode Base64 to text — supports Base64URL (JWT), UTF-8/Latin1, padding toggle, and auto-detect.

Base64 Decode

Decode Base64 strings to readable text instantly with UTF-8 support

Base64URL Encode

Encode text to URL-safe Base64URL format for JWTs and URLs

Base64URL Decode

Decode Base64URL strings from JWTs and URLs to readable text

Text to Base64

Convert plain text to Base64 encoding instantly

URL Encoder & Decoder

Encode or decode URL strings and query parameters using percent-encoding (UTF-8)

HTML Escape & Unescape

Escape HTML characters into entities or unescape entities back to text (safe for XSS-sensitive output)

JSON Formatter & Validator

Format, validate, beautify, and minify JSON — instantly detect errors and debug API payloads safely in your browser.

JWT Decoder

Decode JWT tokens locally to inspect header + payload claims (exp/nbf/iat, iss/aud, scopes/roles) and debug OAuth2/OIDC authentication issues.

What is Base64 Encode?

Base64 Encode

What is Base64 Encode?

How to Use

Common Use Cases

Key Features

UTF-8 Base64 encoding

Standard Base64 output

Padding support

Fast, local processing

Copy-ready output

Auto-detect UX

Practical examples

Related Articles

Base64 Encoding and Decoding: Complete Developer Guide

Quick Examples

Encode simple text

Encode Unicode text (UTF-8)

Encode JSON for a config/env var

HTTP Basic Auth credentials

Encode a JWT-like JSON claims payload (for testing)

Encode a multiline value (cert/key snippet example)

Encode a URL-safe-ish payload (use Base64URL for real URLs)

Encode XML / SOAP payload fragment

Common Questions

What is Base64 encoding?

What is Base64 encoding?

Is Base64 encryption? Is it secure?

Is Base64 encryption? Is it secure?

Why does Base64 increase size by ~33%?

Why does Base64 increase size by ~33%?

What’s the difference between Base64 and Base64URL?

What’s the difference between Base64 and Base64URL?

What is Base64 padding (=) and do I need it?

What is Base64 padding (=) and do I need it?

How do I Base64 encode a string in JavaScript?

How do I Base64 encode a string in JavaScript?

How do I Base64 encode in Node.js?

How do I Base64 encode in Node.js?

Can I Base64 encode JSON?

Can I Base64 encode JSON?

Why does my decoded text look broken or like � characters?

Why does my decoded text look broken or like � characters?

When should I NOT use Base64?

When should I NOT use Base64?

Related Tools

Base64 Encoder / Decoder

Base64 Decode

Base64URL Encode

Base64URL Decode

Text to Base64

URL Encoder & Decoder

HTML Escape & Unescape

JSON Formatter & Validator

JWT Decoder

Base64 Encode

What is Base64 Encode?

How to Use

Common Use Cases

Key Features

UTF-8 Base64 encoding

Standard Base64 output

Padding support

Fast, local processing

Copy-ready output

Auto-detect UX

Practical examples

Related Articles

Base64 Encoding and Decoding: Complete Developer Guide

Quick Examples

Encode simple text

Encode Unicode text (UTF-8)

Encode JSON for a config/env var

HTTP Basic Auth credentials

Encode a JWT-like JSON claims payload (for testing)

Encode a multiline value (cert/key snippet example)

Encode a URL-safe-ish payload (use Base64URL for real URLs)

Encode XML / SOAP payload fragment

Common Questions

What is Base64 encoding?

What is Base64 encoding?