Base64URL is a URL-safe variant of Base64 that replaces + with - and / with _ to avoid issues in URLs, filenames, and HTTP headers. It's the standard encoding for JWT tokens.

When should I use Base64URL instead of Base64?

Use Base64URL when the encoded data will appear in URLs, query parameters, filenames, or JWT tokens. Use standard Base64 for other cases like HTTP headers or JSON payloads.

Do JWTs use Base64URL?

Yes. JWT tokens use Base64URL encoding for the header and payload segments. This ensures the token can be safely transmitted in URLs and HTTP headers.

Should I include padding in Base64URL?

JWT specifications typically omit padding (=) from Base64URL strings. However, some systems require it. This tool lets you choose.

Can I decode Base64URL with a regular Base64 decoder?

Not reliably. You need a Base64URL decoder that handles - and _ characters. Regular Base64 decoders expect + and / instead.

Base64URL Encode

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

Text (Plain)

Auto-detect: paste text to encode

Input

Mode

Encoding

No padding

Base64 (Encoded)

Spacer

Output

What is Base64URL Encode?

Encode text to Base64URL format, a URL-safe variant of Base64 used in JWTs (JSON Web Tokens), URLs, and filenames. Base64URL replaces + with - and / with _ to avoid issues in URLs and file systems. This format is essential for creating JWT tokens, URL parameters, and any Base64 data that needs to be URL-safe.

How to Use

Paste or type the text you want to encode

The tool encodes to Base64URL format

Copy the URL-safe Base64URL output

Use in JWTs, URLs, or filenames safely

Common Use Cases

Create JWT token segments (header and payload)

Encode data for URL query parameters

Generate URL-safe tokens and identifiers

Create safe filenames from encoded data

Encode data for OAuth and SAML flows

Key Features

Instant Base64URL encoding

URL-safe output (- and _ instead of + and /)

UTF-8 character encoding support

Optional padding control

One-click copy to clipboard

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 JWT header

Create JWT header segment

{"alg":"HS256","typ":"JWT"}

Encode for URL parameter

Create URL-safe encoded parameter

user:12345|role:admin

Encode token data

Create URL-safe token identifier

session-token-abc123

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.

Base64URL Decode

Decode Base64URL strings from JWTs and URLs to readable text

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 to Base64URL

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

JWT Decoder

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

URL Encoder & Decoder

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

Base64URL Encode

What is Base64URL Encode?

How to Use

Common Use Cases

Key Features

Related Articles

Base64 Encoding and Decoding: Complete Developer Guide

Quick Examples

Encode JWT header

Encode for URL parameter

Encode token data

Common Questions

What is Base64URL?

What is Base64URL?

When should I use Base64URL instead of Base64?

When should I use Base64URL instead of Base64?

Do JWTs use Base64URL?

Do JWTs use Base64URL?

Should I include padding in Base64URL?

Should I include padding in Base64URL?

Can I decode Base64URL with a regular Base64 decoder?

Can I decode Base64URL with a regular Base64 decoder?

Related Tools

Base64 Encoder / Decoder

Base64URL Decode

Base64 Encode

Text to Base64URL

JWT Decoder

URL Encoder & Decoder

Base64URL Encode

What is Base64URL Encode?

How to Use

Common Use Cases

Key Features

Related Articles

Base64 Encoding and Decoding: Complete Developer Guide

Quick Examples

Encode JWT header

Encode for URL parameter

Encode token data

Common Questions

What is Base64URL?

What is Base64URL?

When should I use Base64URL instead of Base64?

When should I use Base64URL instead of Base64?

Do JWTs use Base64URL?

Do JWTs use Base64URL?

Should I include padding in Base64URL?

Should I include padding in Base64URL?

Can I decode Base64URL with a regular Base64 decoder?

Can I decode Base64URL with a regular Base64 decoder?

Related Tools

Base64 Encoder / Decoder

Base64URL Decode

Base64 Encode

Text to Base64URL

JWT Decoder

URL Encoder & Decoder