About PortJar
A free, fast, ad-supported network toolkit for engineers, sysadmins, and DevOps teams. Built by an engineer who got tired of bouncing between paywalled single-purpose sites.
What it is
PortJar is 29 network and infrastructure tools across 5 categories — DNS, IP & routing, connectivity & diagnostics, email, and utilities.
Why it exists
Most engineers keep a folder of network tool bookmarks: one site for DNS lookup, another for SPF parsing, a third for TLS inspection, a fourth for CIDR math. Half are behind email gates. The other half make you sit through interstitial ads before they show a single result.
PortJar is the toolkit that should already exist: everything in one place, no signup, no email, no interstitials, no “upgrade to view advanced features.” Server-side tools run with proper SSRF guards and rate limits so the service stays usable for everyone. Client-side tools (CIDR, hash, regex, encoders) run entirely in your browser — nothing hits our server.
How it stays free
PortJar is ad-supported. We don't run an ad network ourselves — when ads launch, they'll come from Google AdSense, with placement designed not to interrupt the workflow. No interstitials, no auto-playing video, no popups, no anchor banners that stick to the screen and follow you.
Ads honour Google Consent Mode v2. If you reject cookies, you'll see contextual (non-personalised) ads only. See the privacy page for the consent details.
How the tools work
Tools that need to reach the network — DNS lookup, WHOIS, port checks, TLS inspection, HTTP headers, RBL, ASN — run on our server. Each request is rate-limited per IP (first 20 are free, then a gentle 2-second pacing kicks in) and the target is validated against an SSRF block list so the tool can't be weaponised to probe internal addresses.
Tools that don't need the network — CIDR / subnet calculator, IP converter, hash generator, password generator, regex tester, MAC formatter, encoders — run entirely client-side. The input never leaves your browser. You can even use those tools offline once the page is cached.
Stack
Next.js 15 App Router, React 19, Tailwind CSS 3, TypeScript strict, Vitest. Hosted on a single AlmaLinux VM behind Cloudflare. Deliberately boring — the goal is reliability, not novelty.
Roadmap
The public roadmap shows what's shipped, what's in progress, and what's being weighed. If you have an opinion, tell us — we ship the ones people care about.
Get in touch
Bug reports, tool requests, or just to say a tool saved you time — email feedback@portjar.com. Security disclosures: see /.well-known/security.txt.