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.

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Building query strings, encoding API parameters, or decoding URLs from logs? This URL encoder/decoder handles both directions — encode plain text into percent-encoded format safe for URLs, and decode percent-encoded strings back to readable text. Supports encodeURI mode (preserves URL structure) and encodeURIComponent mode (encodes everything including slashes). Works with UTF-8, emoji and international characters.

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

When should I encode a URL and when should I decode it?

Encode when: building URLs dynamically in code, adding user input to query strings, generating links for emails or documents. Decode when: reading URL parameters from logs, debugging API requests, displaying URLs to users. Rule of thumb: encode before sending (embed in URL), decode after receiving (extract from URL).

How do I encode special characters in URL parameters?

Use encodeURIComponent() for individual values. Characters encoded: space→%20, &→%26, =→%3D, +→%2B, /→%2F, ?→%3F, #→%23, @→%40. Characters NOT encoded (safe): A-Z, a-z, 0-9, - _ . ! ~ * ' ( ). In Python: urllib.parse.quote(value, safe=''). Note: + in a query string means space — use %2B to include a literal plus.

How do emoji and international characters get encoded in URLs?

Unicode characters are first converted to UTF-8 bytes, then each byte is percent-encoded. For example: 😀 → UTF-8 bytes [0xF0, 0x9F, 0x98, 0x80] → %F0%9F%98%80. São → S%C3%A3o (ã = U+00E3 → UTF-8 [0xC3, 0xA3] → %C3%A3). International domain names (IDN) use Punycode encoding instead: münchen.de → xn--mnchen-3ya.de.

What characters are safe in URLs without encoding?

RFC 3986 defines "unreserved" characters that never need encoding: A-Z, a-z, 0-9, hyphen (-), underscore (_), period (.), tilde (~). "Reserved" characters have special meaning and must be encoded when used as data: : / ? # [ ] @ ! $ & ' ( ) * + , ; =. Everything else (spaces, unicode, control chars) must always be encoded. When in doubt, encode — browsers are forgiving but servers may not be.