Open Graph Preview
Fill in meta info and preview share card style (local simulation). 100% free, runs locally in your browser—nothing is uploaded to our servers.
robots.txt Generator
Check common rules and generate robots.txt text. 100% free, runs locally in your browser—nothing is uploaded to our servers.
Sitemap Generator
Generate sitemap.xml fragment from URL list. 100% free, runs locally in your browser—nothing is uploaded to our servers.
CSP Builder
Toggle Content Security Policy directives and export header value. 100% free, runs locally in your browser—nothing is uploaded to our servers.
Permissions-Policy
Feature policy header builder with explanations. 100% free, runs locally in your browser—nothing is uploaded to our servers.
.env Parser
Paste env file and view as table (one-click value masking). 100% free, runs locally in your browser—nothing is uploaded to our servers.
Security Headers Cheat Sheet
Common HTTP security header descriptions and one-click copy examples. 100% free, runs locally in your browser—nothing is uploaded to our servers.
Whois Lookup
Query domain Whois information via RDAP protocol.
DNS Query
Query DNS records via DNS-over-HTTPS.
ICP Filing Query
Query website ICP filing information.
My Public IP
Query your current public IP address and geo info.
Browser Fingerprint
Detect browser UA, screen, Canvas fingerprint, etc.
Port Scanner
Check if a specific port is open on a host, with common port quick-check. 100% free, runs locally in your browser—nothing is uploaded to our servers.
DNS over HTTPS
Resolve domain names using DoH protocol.
URL Parser
Decompose URL and query parameters into a table. 100% free, runs locally in your browser—nothing is uploaded to our servers.
Punycode
Internationalized domain name xn-- and Unicode. 100% free, runs locally in your browser—nothing is uploaded to our servers.
Data URL
Convert between file and data: Base64. 100% free, runs locally in your browser—nothing is uploaded to our servers.
File Type Sniff
Guess type by magic bytes (PNG/PDF/ZIP etc.). 100% free, runs locally in your browser—nothing is uploaded to our servers.
MIME Lookup
Extension and MIME type reference. 100% free, runs locally in your browser—nothing is uploaded to our servers.
HTML Formatter
Indent and minify (js-beautify). 100% free, runs locally in your browser—nothing is uploaded to our servers.
SVG Formatter
SVG/XML validation and indentation. 100% free, runs locally in your browser—nothing is uploaded to our servers.
Markdown Live Preview
Live preview with blog-style rendering. 100% free, runs locally in your browser—nothing is uploaded to our servers.
HTTP Status Codes
Common codes lookup and search. 100% free, runs locally in your browser—nothing is uploaded to our servers.
User-Agent
Rough UA string parsing. 100% free, runs locally in your browser—nothing is uploaded to our servers.
Key Code
Debug keydown key / code values. 100% free, runs locally in your browser—nothing is uploaded to our servers.
Color Converter
Convert between HEX, RGB, HSL and copy as CSS. 100% free, runs locally in your browser—nothing is uploaded to our servers.
Color Contrast
WCAG foreground/background contrast ratio. 100% free, runs locally in your browser—nothing is uploaded to our servers.