JSON URL Encode Decode

About This Tool

URL encoding converts JSON into a format safe for use in URLs. This tool runs entirely in your browser — no data is ever sent to a server. Free to use, no account required.

What JSON URL Encoding Is

URL encoding (percent-encoding) makes JSON safe to include in a URL by replacing special characters with their percent-encoded equivalents.

Why JSON Needs URL Encoding

JSON uses characters that have reserved meaning in URLs: { and } delimit objects, [ and ] delimit arrays, : separates keys and values, " wraps strings. Without encoding, these characters break URL parsing.

What Gets Encoded

The most commonly encoded characters are: { → %7B, } → %7D, [ → %5B, ] → %5D, " → %22, : → %3A, , → %2C, and space → %20. The encoded string is longer but unambiguous in any URL context.

Common Use Cases for JSON URL Encoding

URL-encoded JSON appears in several web development scenarios, particularly with GET request parameters and debugging.

Passing JSON in Query Strings

Some APIs accept complex filter or options objects as query string parameters. For example: GET /items?filter=%7B%22status%22%3A%22active%22%7D. This is valid for small JSON objects in GET requests.

Debugging API Requests

Browser devtools, server logs, and proxy tools often show encoded URLs. Decoding the parameters reveals the original JSON structure, which is essential for debugging API integrations.

URL Encoding JSON: Reference Guide

URL-encoding JSON is necessary when passing JSON data in query parameters, cookies, or URL fragments. It replaces special characters with percent-encoded equivalents.

URL Encoding Example

// Original JSON
{"name": "Alice Johnson", "city": "New York", "active": true}

// URL Encoded
%7B%22name%22%3A%22Alice%20Johnson%22%2C%22city%22%3A%22New%20York%22%2C%22active%22%3Atrue%7D

// As query parameter
https://api.example.com/search?filter=%7B%22name%22%3A%22Alice%22%7D

// JavaScript
const json = {"name": "Alice", "city": "New York"};
const encoded = encodeURIComponent(JSON.stringify(json));
const decoded = JSON.parse(decodeURIComponent(encoded));

Characters Requiring Encoding

Encoding Methods Comparison

JSON URL Encoding: How It Works

Percent-encoding converts special characters in JSON into safe sequences. Every character that is not a letter, digit, or one of -_.!~*'() is replaced with %XX where XX is the hexadecimal ASCII code for that character.

// These characters must be encoded in URLs:
// { } [ ] : " , space and more

const jsonObj = {"name": "Alice Smith", "role": "admin"};
const jsonStr = JSON.stringify(jsonObj);
// '{"name":"Alice Smith","role":"admin"}'

const encoded = encodeURIComponent(jsonStr);
// '%7B%22name%22%3A%22Alice%20Smith%22%2C%22role%22%3A%22admin%22%7D'

// Use in a URL
const url = `https://api.example.com/search?filter=${encoded}`;

// Decode on the server
const decoded = decodeURIComponent(encodedParam);
const data = JSON.parse(decoded);

URL Encode vs Base64 Encode for JSON

Passing JSON in Different HTTP Locations