Small, fast utilities for people who work with proxies, scrapers and networks. No login, no ads — each tool runs in your browser or against a single read-only endpoint.
Request one URL from a datacenter IP and residential IPs at once, and see which of them gets blocked.
What your HTTP client gives away: header order, missing client hints, and contradictions with your user-agent.
Five questions and a straight answer, including when the answer is that you do not need proxies at all.
Your public IP address, the country it resolves to, reverse DNS and the headers your browser sends.
Derive how many proxies a job needs from volume, deadline, per-IP rate limit, concurrency and retries.
Check a path against a pasted robots.txt and see the exact rule that allowed or disallowed it.
Paste a curl command and read it back as Python, Node.js, Go or PHP, with the flags translated properly.
Turn a proxy host, port and credentials into working curl, Python, Node.js and Scrapy snippets.
Network address, broadcast, usable range and host counts for any CIDR prefix length.
Decode any user-agent string into browser, engine, OS and device, including bots and HTTP libraries.
Node4 builds proxy infrastructure — datacenter, residential and rotating proxies with HTTP(S) and SOCKS5 support. These are the small utilities we reach for while working on that infrastructure, published for anyone to use. If they save you a search, bookmark them; if you need the proxies themselves, the pricing page is one click away.