How-to guides
What UUIDs are, the different versions (v1, v4, v5), how ULID and NanoID compare, and when to use each for database keys and APIs.
JAY
How cryptographic hash functions work, MD5 vs SHA-256, why MD5 is broken for passwords, proper password hashing, and how to generate any hash free online.
JAY
Every DNS record type explained — A, AAAA, CNAME, MX, TXT, NS — what they do, when to use them, and how to look up any domain records free.
JAY
What SSL certificates are, how HTTPS encryption works, what certificate errors mean, and how to check any SSL certificate free instantly online.
JAY
What subdomains are, why finding them matters for security research, how subdomain discovery techniques work, and how to find all subdomains of any domain free.
JAY
How to tell if a website is down for everyone or just you, the most common causes, and how to check any site status free in seconds.
JAY
How anonymous links work — HTTP redirects, client-side techniques, Referrer-Policy headers — what they protect against, their limits, and how to create anonymous links free.
JAY
Every Referrer-Policy value explained — what each does, when to use it, how to implement in Apache, Nginx and PHP, and which policy suits your site type.
JAY
The complete guide to the HTTP Referer header — what it is, how it works, what it exposes, who reads it, legal implications under GDPR, and how to control it.
JAY