☕ on the menu · Knowledge Base

The Knowledge Base.

Clear, modern explainers for the fundamentals, written to be read once and remembered. This is the “KB” in KB Cafe: references that feed straight into the matching tools.

Concepts
Object-Oriented Programming concepts
Encapsulation, abstraction, inheritance, polymorphism, the four pillars, with examples.
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Concepts
Software design patterns
The classic Gang-of-Four patterns, creational, structural, behavioral, and when to use them.
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Concurrency
Multithreading & concurrency explained
Threads vs processes, race conditions, locks, deadlocks, and writing thread-safe code.
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Memory
Memory leaks explained
What a memory leak is, the common causes across languages, and how to find and prevent them.
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Memory
Smart pointers & RAII
Reference counting, ownership, and how unique/shared pointers stop leaks at the source.
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C++
Type casting in C++
static_cast, dynamic_cast, const_cast and reinterpret_cast, what each one actually does.
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C#
C# (C-sharp)
The language and .NET, the type system, and the features that define it: LINQ, async/await, generics, records.
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Data formats
What is JSON?
JavaScript Object Notation: the syntax, the six data types, JSON vs XML, and why it runs every API and AI call.
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Data formats
What is XML?
Elements, attributes, the tree, well-formed vs valid, namespaces, and the XML behind every RSS and Atom feed.
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Feeds
What is RSS?
Feeds, readers, the orange XML buttons, and how RSS and Atom differ, the basics, clearly.
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Networking
What is DNS?
The internet's address book: how resolution works, every record type, TTL and propagation, and how to set records up.
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Networking
What is WHOIS?
Domain registration records: WHOIS vs RDAP, the status codes, why registrant data is redacted, and keeping yours healthy.
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Networking
HTTP explained
Methods, status codes, headers, and the request/response cycle behind every web call.
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Email
How SMTP works (sending email)
The protocol that moves email, the SMTP conversation, envelopes, and why mail gets blocked.
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Email
POP3 vs IMAP (reading email)
The two protocols for retrieving mail, how they differ, and which one you actually want.
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Email
Why your email goes to spam (deliverability)
The 4 reasons legit mail lands in spam, how SPF, DKIM, and DMARC work together, and how to diagnose and fix it.
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Email
DMARC explained
The umbrella over SPF and DKIM: alignment, the none/quarantine/reject policy progression, reports, and a safe rollout.
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Email
SPF explained
The record that says who may send for your domain: mechanisms, ~all vs -all, the forwarding break, and the 10-lookup limit.
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Email
DKIM explained
Cryptographic email signing: how the signature and selector work, what they protect, and why DKIM survives forwarding.
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Networking
How ping & ICMP work
What ping really measures, the ICMP echo request/reply, TTL, and reading the results.
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Networking
Port scanning explained
What a network port is, how a port scan works, the common scan types, and what they reveal.
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Shell
Shell scripting explained
Bash basics, the shebang, variables and quoting, pipes and redirection, and the gotchas that bite.
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Shell
Cron explained
Crontab's five fields, ranges and steps, named shortcuts, the day-of-month vs day-of-week OR gotcha, and why jobs fail.
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Front-end
How to start CSS
What CSS is, the three ways to add it, selectors, the box model, sane sizing, and a live editor to try it in.
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Agentic AI
Build your own agentic OS
A local-first command center where a coding agent works over your own notes and tools, with saved rules, routines, and verify loops. The real primitives (CLAUDE.md, slash commands, skills, subagents, MCP), the security you need, and a builder that writes a routine for you.
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Version control
Git and version control
What version control is, the working-tree, staging, commit, and remote model, the everyday commands, branches, the gotchas (gitignore, secrets, conflicts), and why it is your safety net with AI coding.
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Monetization
Monetize a YouTube channel with AI
Use AI as your strategist to plan, package, script, and diversify a channel, grounded in the real 2026 Partner Program thresholds, the honest economics, and the AI-content policy that demonetizes 'slop'. With an eligibility checker and 8 rebuilt prompts.
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More on the way

KB Cafe’s reference shelf is being rebuilt from its long history as a developer resource, evergreen topics first (encoding, concurrency, memory), each rewritten for how we build today. Need a tool instead? The menu has the Base64 encoder, JSON → TypeScript, JWT decoder, and cron generator.