Human-reviewed directory
Resources
Useful websites, tools, guides, courses, communities, and references with original editorial notes.
Security Headers
Quickly checking whether a public website sends common defensive headers
MDN HTTP Observatory
Reviewing public HTTP security headers and related website configuration
Qualys SSL Labs Server Test
Reviewing the public TLS and HTTPS configuration of a website server
VirusTotal
Comparing a non-confidential file, URL, domain, or hash across security engines
Have I Been Pwned
Checking whether an email appears in known breach data
NOAA Data Access Viewer
Finding U.S. coastal elevation, imagery, land cover, and related datasets
OpenTopoMap
Viewing a topographic-style map built from OpenStreetMap and elevation data
USGS EarthExplorer
Finding satellite imagery, aerial photography, elevation, and land data
Copernicus Browser
Searching and visualizing European Copernicus satellite imagery
Natural Earth
Small-scale global basemap data for regional and world maps