Base64URL Encoder/Decoder

Base64URL Encoder/Decoder | Online Free Tool | Elysia Tools

Tool usage guide

Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Category: Format Conversion
Input types: textarea, select
Output type: text
Sample coverage: 4
API ready: Yes

Overview

The Base64URL Encoder/Decoder is a specialized utility designed to convert text and binary data to and from the URL-safe Base64 variant (RFC 4648 / RFC 7515) commonly used in JWT, JWS, and JWE. It also enables seamless conversion between standard Base64 and Base64URL formats, with support for UTF-8 and Hex output encodings.

When to use

When generating or parsing JWT headers and payloads that require URL-safe Base64 encoding without padding characters.
When transmitting binary data or tokens via URL query parameters where standard Base64 characters like '+' and '/' could cause routing or parsing issues.
When converting existing standard Base64 strings into the URL-safe Base64URL format, or vice versa.

How it works

1Input the text, standard Base64, or Base64URL string into the input area.
2Select the desired operation: Encode to Base64URL, Decode from Base64URL, Standard to Base64URL, or Base64URL to Standard.
3Choose the output encoding format (UTF-8 text or Hex string) if you are decoding.
4The tool processes the input instantly and displays the converted output.

Use cases

Debugging and inspecting JWT tokens by decoding the header and payload segments.
Preparing binary identifiers or tokens for safe transmission in URL query parameters.
Converting legacy standard Base64 database entries into URL-safe strings for API integrations.

Examples

1. Decoding a JWT Payload Segment

Web Developer

Background

A developer needs to inspect the JSON payload of a JWT token received from an authentication service to verify the user claims.

Problem

The payload is encoded in URL-safe Base64 without padding, making it unreadable.

How to use

Paste the payload segment of the JWT into the input field, select 'Decode from Base64URL' as the operation, and set the output encoding to 'UTF-8 text'.

operation: "decode", outputEncoding: "utf-8"

Outcome

The tool outputs the decoded JSON string containing the user claims.

2. Converting Standard Base64 to URL-Safe Base64

API Integrator

Background

An integrator has a standard Base64 encoded API key containing '+' and '/' characters that needs to be passed as a URL path parameter.

Problem

The standard Base64 characters will break the URL routing.

How to use

Paste the standard Base64 string into the input field and select the 'Standard → Base64URL' operation.

FAQ

What is the difference between standard Base64 and Base64URL?

Base64URL replaces the '+' and '/' characters of standard Base64 with '-' and '_', and omits the '=' padding characters to make the string safe for URLs and filenames.

Can I decode a JWT payload using this tool?

Yes, you can paste individual segments of a JWT (header or payload) and decode them from Base64URL to UTF-8 text.

Does this tool support decoding to hexadecimal format?

Yes, you can set the output encoding option to Hex string when decoding Base64URL.

Why does Base64URL omit the '=' padding characters?

The '=' character is often URL-encoded or has special meaning in query strings, so Base64URL strips it to prevent transmission issues.

Is this tool compliant with RFC standards?

Yes, the encoding and decoding processes follow the specifications outlined in RFC 4648 and RFC 7515.

operation: "to-base64url"

3. Encoding a String to Base64URL

Security Engineer

Background

A security engineer needs to encode a custom token string into a URL-safe format for a webhook payload.

Problem

The token must be transmitted safely in a URL without escaping special characters.

How to use

Input the raw token text, select 'Encode to Base64URL' as the operation, and run the encoder.

operation: "encode"

Outcome

The input is encoded into a compact, URL-safe Base64URL string.

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Inputs

Result

Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Overview

When to use

How it works

Use cases

Examples

1. Decoding a JWT Payload Segment

2. Converting Standard Base64 to URL-Safe Base64

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3. Encoding a String to Base64URL