PortJar is a free, no-signup network engineer toolkit that consolidates 29 single-purpose tools into one clean interface. Built to eliminate the need to context-switch between 8 different bookmarked sites for 30-second tasks. Tools span DNS lookup, WHOIS, port checking, TLS inspection, SPF/DMARC validation, CIDR/subnet calculator, hash generators, regex testers, and encoders. Client-side tools (CIDR, hash, regex, encoders) run entirely in the browser. Server-side tools (DNS, WHOIS, port, TLS, SPF) run with SSRF guards and tiered rate limiting — first 10 requests free, then paced. Built on Next.js 15 + React 19 + Tailwind. Each tool detail page ships ~4KB of route JS on top of a 102KB shared runtime.