Guides
Long-form guides organized by pillar. Every guide is sourced to primary documentation and paired with a working tool where one exists.
tls-certs
Why your ACME renewal quietly broke last month
Let's Encrypt changed its intermediates, dropped an EKU, killed OCSP, and started shortening lifetimes. None of it throws a renewal error. Here is what to check.
tls-certs
Certificate Transparency explained for devs
The plain-English explanation of Certificate Transparency logs — what they contain, who runs them, and why they matter for every domain you own or ship code to.
kubernetes
Cron syntax, actually explained
The five standard cron fields, the Quartz six and seven field variants, macros, step values, the day-of-month versus day-of-week OR rule, and the timezone traps.
tls-certs
How to find every subdomain with CT logs
Certificate Transparency logs are the most complete public record of a company's hostnames. How to query them, clean the output, and run it as a standing control.
web-dev
Every HTTP status code, and when it shows up
A working reference to the HTTP status codes you will actually meet in production, what each one really means, and the pairs everyone confuses.
tls-certs
JWT, decoded: parts, algorithms, pitfalls
What the three parts of a JWT contain, how the signing algorithms differ, which claims you must validate, and the practices RFC 8725 tells you to adopt.
kubernetes
Karpenter vs cluster-autoscaler in 2026
Both node autoscalers are now SIG Autoscaling subprojects, and in July 2026 they started sharing an API. What actually differs, and how to choose.
kubernetes
kubectl cheatsheet (2026 edition)
A working kubectl reference for Kubernetes 1.36: output formats, JSONPath, debug workflows, server-side apply, drain safety, and the version skew rules.
tls-certs
How to read a TLS certificate
A field guide to the X.509 fields that actually matter — SAN, EKU, validity, basic constraints, SCTs — and the misreads that waste an afternoon of debugging.
web-dev
Regex patterns you will actually use
A working regex reference: the syntax worth memorizing, patterns for logs, semver, URIs and email, flag semantics, dialect differences, and how to avoid ReDoS.
sre
SLOs, SLIs, and error budgets: a primer
How to pick service level indicators, set an achievable objective, calculate an error budget, and alert on burn rate instead of paging on every blip.
yaml-json
The YAML + JSON config reference
How YAML and JSON really differ, why YAML 1.1 versus 1.2 keeps breaking configs, and the type coercion traps that bite Kubernetes, Helm, and Ansible users.