SQL & Relational Database Fundamentals
Test joins, keys, normalization, indexes, transactions, aggregation, NULL behavior, and safe query design.
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Modern PHP Web Development
Challenge your PHP knowledge with types, arrays, requests, sessions, PDO, namespaces, errors, security, and web application structure.
React Components, State & Effects
Test component rendering, props, state, keys, effects, context, controlled inputs, and practical React design decisions.
Web Performance & Core Web Vitals
Reason through loading, rendering, images, JavaScript, caching, metrics, fonts, and evidence-based performance improvements.
UX, Interface Design & Design Systems
Test usability, hierarchy, feedback, forms, navigation, research, tokens, components, and coherent interface systems.
Node.js Events: Listeners, Ordering & Cleanup
Follow event delivery, remove listeners correctly and distinguish events from promises.
Node.js Data: Buffers, Paths & File Contracts
Reason about bytes, text encodings and portable file paths without relying on platform guesses.
Python Iterators: Lazy Pipelines & Exhaustion
Track consumption, laziness and exhaustion in practical data pipelines.
Python Objects: Instance State & Data Classes
Distinguish shared class state, instance attributes and generated data-class behavior.
SQL Windows: Ranking, Partitions & Running Totals
Understand row-preserving analytics and make ordering and window frames explicit.
SQL Reliability: Transactions, Constraints & Recovery
Protect data consistency and distinguish statement failures from transaction-level decisions.
Apps Script Sheets: Range Shapes & Batch Writes
Match spreadsheet coordinates to arrays and avoid stale rows, shape errors and unnecessary calls.
Apps Script Dates: Time Zones & Calendar Boundaries
Avoid date shifts by distinguishing instants, calendar dates and formatting zones.
AI Workflows: Tool Calls, Approval & Recovery
Design AI-assisted actions with clear boundaries, useful observations and deliberate recovery.
Browser URLs: Query Parameters & Navigation
Build and inspect URLs correctly, preserve repeated parameters and distinguish navigation behavior.
TypeScript: Narrowing & Data Contracts
Practice union narrowing, optional values, type assertions, and the boundary between static types and runtime data.
Browser Files: Images, Blobs & Downloads
Reason about selected files, object URLs, canvas exports, image sizing, and download workflows.
CSV & JSON: Reliable Imports and Exports
Practice CSV quoting, JSON value rules, column mapping, duplicate handling, and faithful data exports.
HTTP Caching: Freshness & Revalidation
Understand cache directives, validators, conditional requests, shared caches, and versioned assets.
CSS Motion: Transforms & Animation Controls
Practice keyframes, transitions, transform order, animation states, and reduced-motion alternatives.
Technical SEO: Crawling & Page Metadata
Make practical decisions about crawlable links, indexing controls, canonical URLs, titles, and sitemaps.
Browser Storage & Offline Workflows
Choose storage APIs and reason about saved state, quotas, service workers, and offline update strategies.
Accessibility: Keyboard & Focus Patterns
Reason about tab order, native controls, modal focus, composite widgets, and visible keyboard interaction.
SVG: Coordinates & Responsive Graphics
Understand SVG viewports, coordinate systems, paths, reusable shapes, and scalable graphics.