Interactive learning
Start with the basics, work through examples and check your understanding with a pop quiz in every section. Pick a topic below.
Networking foundations
Understand address boundaries, sizing and route summaries.
APIs and data
Move from structured data to secure, reliable integrations.
Learn JSON
JSON has objects, arrays, strings, numbers, booleans and null. Strings and object keys use double quotes.
Start lesson →Step 2 of 5 · varied quizzesLearn HTTP
A method and URI express intent. Status, headers and content express the outcome.
Start lesson →Step 3 of 5 · varied quizzesLearn REST APIs
Resource-oriented APIs expose identifiers and representations through HTTP semantics. Stateless requests carry their processing context.
Start lesson →Step 4 of 5 · varied quizzesLearn API Authentication
Authentication establishes the caller. Authorisation decides which actions are permitted.
Start lesson →Step 5 of 5 · varied quizzesLearn Webhooks
Webhooks are event callbacks. Delivery may be duplicated or delayed.
Start lesson →Automation and distributed systems
Build scheduled and event-driven work with bounded failure handling.
Learn Cron
Five-field cron specifies minute, hour, day-of-month, month and weekday. Use an explicit timezone.
Start lesson →Step 2 of 4 · varied quizzesLearn Automation
Reliable automation validates input, controls side effects and defines failure paths.
Start lesson →Step 3 of 4 · varied quizzesLearn Queues
Queues buffer work. At-least-once delivery permits duplicates.
Start lesson →Step 4 of 4 · varied quizzesLearn Event-Driven Architecture
Events describe past facts. Consumers react independently under explicit delivery contracts.
Start lesson →AI systems
Plan context, evidence, controls and adaptive tool use.
Learn LLM Context Windows
Context is a finite token budget. Instructions, history, evidence and output reservations all consume it.
Start lesson →Step 2 of 4 · varied quizzesLearn RAG
Retrieval places external evidence in the prompt. It does not guarantee a correct answer.
Start lesson →Step 3 of 4 · varied quizzesLearn AI Workflows
AI outputs are proposals until validation and appropriate review make them usable.
Start lesson →Step 4 of 4 · varied quizzesLearn AI Agents
Agents choose tools or steps toward a goal. Adaptive behaviour needs explicit permissions and limits.
Start lesson →Infrastructure resilience
Compare storage capacity, disk-failure tolerance and backup.
Email authentication and DNS
Understand sending authorisation, signatures, identifier alignment, reporting and safe enforcement.
Learn SPF
SPF authorises hosts to use a domain in the SMTP MAIL FROM or HELO identity. It does not authenticate the visible From address by itself.
Start lesson →Step 2 of 3 · varied quizzesLearn DKIM
DKIM signs selected message headers and the body with a private key. Receivers retrieve the matching public key from a selector under the signing domain.
Start lesson →Step 3 of 3 · varied quizzesLearn DMARC
DMARC passes when at least one validated SPF or DKIM identifier aligns with the RFC5322.From domain. It also publishes handling preferences and reporting destinations.
Start lesson →