Skills
General-purpose programming languages
Query languages
SQL
![Skill: GraphQL](/assets/skills/graphql-69164d42.png)
Markup languages
Stylesheet languages
Scripting languages
Data interchange formats
![Skill: SDMX data interchange format](/assets/skills/data interchange formats/SDMX-df05fbeb.png)
CSV
Lightweight markup languages
![Skill: MDX (Markdown for the Component Era)](/assets/skills/lightweight markup languages/mdx-8af608b4.png)
Template systems
![](/assets/skills/templates/handlebars-5cc3cb69.png)
eRuby
![](/assets/skills/templates/slim-1676ca5b.png)
Frameworks
E-commerce
![](/assets/skills/e-commerce/dolibarr-0bc3c875.png)
Help desks
Databases
LMDB
BDB
Database administration
MongoDB Compass
![](/assets/skills/adminer-31c25ce0.png)
Backup tools
mysqldump
mariadb-dump
Duplicity
Synology Cloud Sync
Synology DiskStation Manager
VCS
![](/assets/skills/gogs-f48ddc0d.png)
Deployment
![](/assets/skills/capistrano-888d7c77.png)
Code editors
API
SOAP
REST
Productivity & collaboration platforms
Network security and tools
![](/assets/skills/nftables-d04655b2.png)
![](/assets/skills/fail2ban-051caea3.png)
![](/assets/skills/glances-b9a38f52.png)
openssl
SSH
SFTP
![](/assets/skills/SFTPGo-f09f55d5.png)
Web servers
HTTP & HTTP/2 & HTTP/3 + QUIC
H2O
App servers
![](/assets/skills/app servers/puma-c80340fb.png)
uWSGI
Web cryptography
TLS 1.3
SNI
HSTS Preload
OCSP stapling
ACME
ECC
Cipher suites
ssldump
![](/assets/skills/ssllabs-d5b9d478.png)
![](/assets/skills/hardenize-b25c0ab9.png)
Cloud service providers
CMS
![](/assets/skills/ghost-c47ec5ab.png)
DNS
![](/assets/skills/powerdns-35d6942a.png)
DNSSEC
DNS over TLS/QUIC
DNS CAA
DNSControl
Operating systems
![](/assets/skills/archlinux-01e5be3f.png)
![](/assets/skills/chromeos-9344108d.png)
![](/assets/skills/gnu-linux-209e6d8b.png)
Package managers
![RubyGems - package manager for the Ruby programming language that provides a standard format for distributing Ruby programs and libraries](/assets/skills/rubygems-f8dec411.png)
![pip - package-management system written in Python and used to install and manage software packages](/assets/skills/pip-adfde5e4.png)
APT
![](/assets/skills/DNF-a745c6ac.png)
pacman & pikaur
Emailing
SMTP/SMTPS
![](/assets/skills/email/postfixadmin-337f2e9c.png)
IMAP/IMAPS
FTS Flatcurve
![](/assets/skills/email/SPF-226673e5.png)
DKIM
![](/assets/skills/email/DMARC-8fbb4f4f.png)
MTA-STS
PTR
![Brand Indicators for Message Identification, or BIMI is a specification allowing for the display of brand logos next to authenticated emails](/assets/skills/email/bimi-0cc9f0e8.png)
SVG Tiny P/S
![Spamhaus Technology - Real-time Blackhole List | IP and domain reputation data](/assets/skills/email/spamhaus-fa0227b3.png)
![UCEPROTECT-Network - Real-time Blackhole List | Spam protection made in Switzerland](/assets/skills/email/UCEPROTECT-ce7adc57.png)
![Use Postmaster Tools to analyze your email performance, and help Gmail route your messages to the right place](/assets/skills/email/Gmail-Postmaster-Tools-f9aec5a2.png)
SNDS & JMRP
![AT&T Yahoo Mail](/assets/skills/email/Currently-AT&T-51bf55aa.png)
Regular expressions
Capturing groups
(Double) escaping
Negative lookahead
Negated character class
Greedy and lazy quantifiers
Global pattern flags
PCRE2 syntax
REGEXP_REPLACE function
![regex101: build, test, and debug regex](/assets/skills/regularexpressions101-0ad5a2f8.png)
Design