How-to guides
Complete guide to wa.me links — URL format, phone number formatting by country, pre-filled messages, URL encoding, QR codes, and tracking performance.
JAY
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.
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What Base64 encoding is, how it works, where you encounter it in APIs and JWTs, why it is not encryption, and how to encode and decode free instantly.
JAY
What JSON Web Tokens are, how the three parts work, critical security implications about payload visibility, and how to decode any JWT free instantly.
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.
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How WHOIS works, what domain registration data it reveals, how privacy protection affects records, and how to look up any domain free instantly.
JAY
What SSL certificates are, how HTTPS encryption works, what certificate errors mean, and how to check any SSL certificate free instantly online.
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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.
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