What is the difference between hostname and host?

hostname is the domain/IP without port (e.g. api.example.com). host includes the port if non-standard (e.g. api.example.com:8080). For standard ports (80 for HTTP, 443 for HTTPS), port is omitted from host.

Is the URL hash (#fragment) sent to the server?

No — the fragment identifier (#hash) is processed entirely by the browser. It is never sent in the HTTP request to the server. This is why React Router and Angular Router use it for client-side navigation without server requests.

What is URL encoding and when is it needed?

URL encoding (percent encoding) converts special characters into %XX hex format. Spaces become %20 or +, & becomes %26, = becomes %3D. Query parameter values must be encoded to prevent ambiguity. Use encodeURIComponent() for values, encodeURI() for full URLs.

What is the maximum URL length?

There is no official RFC limit, but practical limits exist: Chrome/Firefox support up to ~2MB, IE/Edge limit at 2048 characters, Apache server default limit is 8192 bytes. For long data, use POST body instead of URL query params.

How do I extract query params from a URL in JavaScript?

Use the URL API: const url = new URL(window.location.href); url.searchParams.get("key") — returns value or null. url.searchParams.forEach((value, key) => ...) — iterate all params. Works in all modern browsers and Node.js 10+.

What is the difference between encodeURI and encodeURIComponent?

encodeURI() encodes a full URL — preserves :, /, ?, =, & characters needed for URL structure. encodeURIComponent() encodes a URL component (single value) — encodes everything including :, /, ?, &. Always use encodeURIComponent() for query parameter values.

🔗

Query String Parser — Extract & Edit URL Parameters Online

Parse · Build · Encode · Diff · Batch — 10 powerful URL tools in one, 100% browser-side

Ctrl+Enter = Parse · Ctrl+L = Clear

🔗

Try:

🔗

Paste a URL to parse

Supports HTTP · HTTPS · FTP · Mailto · Custom protocols

📂 10 Features⚡ Instant Parse🔒 100% Browser-side📋 Smart Copy

Ctrl+Enter ParseCtrl+L ClearCtrl+S Download JSONCtrl+Shift+C Copy output1 Overview2 Params3 Validate4 Encode

💡

The query string is where URLs carry data — search terms, filters, tracking codes, API keys and pagination. This query string parser decodes the raw ?key=value&key2=value2 string into a clean, editable parameter table. View all parameters at once, decode percent-encoded values, spot duplicates, and add or remove parameters to rebuild the URL. Essential for API development, UTM tracking analysis and debugging search filters.

What is a URL Parser?

A URL (Uniform Resource Locator) parser breaks a web address into its individual components: protocol (scheme), username, password, hostname, port, pathname, query string (search params), and hash fragment. This tool uses the browser's native URL API for 100% accurate parsing — the same engine your browser uses — with zero server requests.

10 Features in This URL Parser

1. Live URL Breakdown — Colour-coded anatomy view showing every URL part. 2. Query Params Editor — Edit, add, delete params with live URL reconstruction. 3. URL Builder — Compose a URL from protocol, host, path, params, and hash. 4. Encode/Decode — encodeURIComponent and encodeURI with quick-load. 5. cURL Generator — One-click cURL command for any HTTP method. 6. URL Diff — Compare two URLs part-by-part, highlight differences. 7. Batch Parser — Parse up to 50 URLs at once, export as CSV. 8. URL Validator — Detect HTTPS issues, credentials, length warnings. 9. Smart Copy — Copy any individual URL part with one click. 10. History — Last 50 parsed URLs with one-click restore.

Frequently Asked Questions

How is a query string structured?

A query string starts with ? and contains key=value pairs separated by & (ampersand). Keys and values are percent-encoded — spaces become %20 or +, special characters become %XX hex sequences. Example: ?name=John%20Doe&city=New+York&age=30. Some parameters repeat with the same key: ?tag=js&tag=css creates an array of tags.

What is the difference between %20 and + in URLs?

Both encode a space, but in different contexts. %20 is the standard percent-encoding for space in any URL component. + encodes space only in application/x-www-form-urlencoded format (HTML form submissions). In query strings, both are commonly accepted. In path segments, only %20 is valid — + is a literal plus sign. decodeURIComponent handles %20; decodeURIComponent does NOT decode +. Use URLSearchParams to decode both correctly.

How do I access query string parameters in JavaScript?

Modern approach using URLSearchParams: const params = new URLSearchParams(window.location.search); const page = params.get("page"); // "1". For multiple values: params.getAll("tag"). To iterate all: for (const [key, val] of params). In Node.js: const url = new URL(req.url, "http://localhost"); url.searchParams.get("id"). Avoid manual string splitting — URLSearchParams handles encoding correctly.

Can query strings have duplicate keys?

Yes — the same key can appear multiple times: ?color=red&color=blue&color=green. How duplicates are handled depends on the server framework: PHP: $_GET["color"] returns "green" (last value). Node.js URLSearchParams: params.getAll("color") returns ["red","blue","green"]. Express.js: req.query.color returns ["red","blue","green"]. This is commonly used for multi-select filters and tag systems.