4 Free Web Developer Utilities
IP Lookup, User Agent Parser & HTTP Codes
Look up IP addresses with geolocation data, parse user agent strings from any browser or device, build query strings for API testing, and reference all HTTP status codes. Essential utilities for web developers.
Web Utilities
HTTP Status Codes Reference
Complete HTTP status codes reference with cause and fix steps. Search 200, 301, 404, 500, 502, 503 and every 1xx-5xx code. Includes Nginx codes and deprecated tags.
IP Address Lookup
Look up any IPv4, IPv6, or domain to get city, country, ISP, ASN, reverse DNS hostname, and timezone. Free instant IP geolocation and IP address lookup tool.
Query String Builder
Build URL query strings visually. Add parameters, toggle rows, choose %20 or + encoding, add #fragments, and copy the full URL instantly. Free URL builder tool.
User Agent Parser
Parse any user agent string to detect browser name, OS, device type, and 30+ bots. Your current UA is auto-loaded. Free user agent parser, 100% private.
Website Status Checker
Check if a website is down for everyone or just you. Get HTTP status code, response time, redirect chain, and a free 4-ping latency test - no sign-up needed.
4 Free Web Developer Utilities for Debugging and Reference
All 4 web utilities run in your browser and return results in seconds. They cover the quick lookups, reference checks, and request-building tasks that web developers deal with regularly -- the kind of thing that should not require a Stack Overflow search or opening a third-party service.
The User Agent Parser takes any user agent string and breaks it down into browser name and version, rendering engine (Blink, WebKit, Gecko, Trident), operating system with named versions (including macOS Sonoma, Ventura, and all major Windows releases), device type and model, and CPU architecture. It also detects 30+ bots and crawlers including Googlebot, GPTBot, Bingbot, and Bytespider. When parsing your own browser it shows a UA Client Hints panel and a Browser & System Info panel with screen resolution, CPU cores, device memory, and timezone.
The IP Address Lookup returns city, region, country, continent, coordinates, postal code, timezone, currency, capital, dial code, and country TLD for any IPv4 address, IPv6 address, or domain name. It also resolves the reverse DNS hostname (PTR record), shows ASN, ISP, and CIDR network block, includes a Google Maps link, and auto-detects your own IP in one click. The HTTP Status Codes Reference covers all 60+ official codes across 1xx--5xx plus Nginx-specific codes (444, 499) and deprecated codes -- each with cause, fix steps, MDN link, and visual badges for Deprecated, Experimental, and Unofficial codes.
The Query String Builder assembles URL query strings visually -- add key-value parameters one at a time, enable or disable individual rows without deleting them, choose from three encoding modes (No encoding, %20 RFC 3986, or + Form encoding), and optionally append a fragment (#hash). Import any existing URL to extract its parameters automatically. Copies as a full URL or just the raw query string.
All tools run entirely in your browser. No files are uploaded to our server.
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Frequently Asked Questions
Everything you need to know
We offer a User Agent Parser, IP Address Lookup, HTTP Status Code Reference, and Query String Builder -- essential tools for web developers and network professionals.
Paste any user agent string and the parser instantly detects the browser family and version, rendering engine (Blink, WebKit, Gecko, Trident), operating system with named versions (including macOS Sonoma, Ventura, and all major Windows releases), device type and model, CPU architecture, and 30+ bots and crawlers including Googlebot, GPTBot, Bingbot, and Bytespider. The raw UA string is displayed with color-coded tokens. When analyzing your own browser, two additional panels appear: UA Client Hints (navigator.userAgentData) and Browser & System Info showing screen resolution, CPU cores, device memory, and timezone.
Yes. Enter any IPv4 address, IPv6 address, or domain name to get city, region, country, continent, coordinates, postal code, timezone, currency, capital city, dial code, country TLD, ASN, ISP, organization, and CIDR network block. A reverse DNS lookup resolves the PTR hostname automatically. A Google Maps link is included for the coordinates, and you can auto-detect your own IP with the My IP button.
It covers all 60+ official HTTP status codes across 1xx--5xx plus Nginx-specific codes (444, 499) and deprecated codes. Each code card shows the cause and actionable fix steps. Every standard code links directly to its MDN documentation page. Codes are tagged with visual badges -- Deprecated, Experimental, WebDAV, Unofficial -- so you know the context before applying a fix. Search by number, name, or keyword to jump straight to the code you need.
Most utilities (user agent parser, HTTP reference, query string builder) are fully client-side. The IP lookup tool makes an anonymized API request to fetch geolocation data for the IP you enter.
Copy the user agent string from your server access log (it appears alongside the request URL and status code) and paste it into the User Agent Parser. It identifies the browser name, version, operating system, device type, and rendering engine in one step -- faster than cross-referencing a user agent database manually.
An ASN (Autonomous System Number) is a unique identifier assigned to a network of IP addresses controlled by a single organization, such as an ISP, cloud provider, or large enterprise. Enter any IP address into the IP Address Lookup tool to see its ASN alongside ISP name, organization, country, and geolocation data.
The Query String Builder helps you assemble URL query strings by adding key-value pairs without worrying about encoding or formatting. Enter your parameters, and the tool outputs a correctly formatted query string with proper percent-encoding. Useful for constructing API test URLs, building deep links for campaigns, and debugging parameter issues without encoding every value manually.
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