CIDR and subnetting: how to read /24, /25 and everything in between
A practical walkthrough of CIDR notation, network and broadcast addresses, usable host counts and how to split a /24 without memorising tables.
Read the guideSecurity
JWT decoding is not verification: what each step actually proves
Decoding a JWT only reveals its claims. Verification checks the signature with a key. Here is why the difference matters for security reviews and debugging.
6 min read · 2026-11-08
Security
The HTTP security headers worth checking — and what bad values look like
A short audit checklist for CSP, HSTS, X-Content-Type-Options, Referrer-Policy, Permissions-Policy and frame protection, with realistic failure examples.
8 min read · 2026-11-08
Networking
DNS record types, plainly explained: A, AAAA, CNAME, MX, TXT and more
What each common DNS record does, when to use it, and the mistakes that cause email and website outages — without assuming a networking certification.
7 min read · 2026-11-08
How to shrink a PDF without turning text into mush
Why PDF compression is really a choice between rasterising pages and cleaning up structure, and how to pick settings that keep a document readable.
6 min read · 2026-11-08
Images
JPEG, PNG or WebP? A practical guide to choosing an image format
Choose an image format based on content, transparency and where the image will be used — with clear guidance on quality settings and when conversion helps.
6 min read · 2026-11-08
Calculators
GST inclusive vs exclusive: a worked invoice example
How to separate CGST and SGST from an inclusive price, how to add GST to an exclusive price, and why the two directions give different totals.
5 min read · 2026-11-08
Calculators
EMI and SIP maths: where the money actually goes
Understand the EMI formula, why early repayments are mostly interest, and how SIP compounding differs — using clearly labelled illustrative numbers.
7 min read · 2026-11-08
Developer
Base64 is not encryption — what encoding actually does
Base64 makes binary data safe for text channels. It does not hide anything. Learn when to use it, when to use encryption instead, and why padding exists.
5 min read · 2026-11-08
Security
SSL certificate checks: expiry, SANs and the mistakes that cause outages
What to verify before a certificate expires, how certificate transparency logs help, and why a browser warning is not always about the date.
6 min read · 2026-11-08