Provide an IP and a port, this service try to access that port and report if that port is open (like nc from public internet).

A database about required open ports for various applications. Useful for setting up firewall and port forwarding rules.

Offers anonymous SMS reciving service with numbers in China.

ftp ipv4.cat
telnet ipv4.cat
ncat ipv4.cat
curl ipv4.cat
http://ipv4.cat

<blockquote>Free illustrations, for everything
Memorable products, brands, & presentations start with our
curated royalty-free illustration library</blockquote>

A flamegraph generator for Postgres EXPLAIN ANALYZE output.

Nicely written illustrations towards various topics via IPython notebooks by Peter Norvig.

<blockquote>A short description and screenshot of some useful command line tools I use that aren't part of typical POSIX environment.</blockquote>

Trade security vulnerability protection for performance boost

IPython notebook with GPU access for free. Similar to Google Colab (https://colab.research.google.com).

A manual on chioce of types of glue to stick various kinds of materials together.

A demo that allows you to experiment with text completion with various text sequence generation models.