Intermediate terms
Canonical URL (rel=canonical)
A <link rel='canonical'> tag that tells search engines which URL is the authoritative version of a page — preventing duplicate content from splitting ranking signals across multiple URLs.
1mo ago
frontend intermediate
Core Web Vitals
Google's three field-measured performance metrics — LCP (loading), INP (interactivity), CLS (visual stability) — used as direct search ranking signals since 2021.
1mo ago
performance intermediate
Cumulative Layout Shift (CLS)
A Core Web Vital that measures unexpected visual movement of page elements during load — caused by images without dimensions, late-injected content, and font swaps. Target: under 0.1.
1mo ago
performance intermediate
Dependency & Supply Chain Security
Protecting applications from malicious or vulnerable third-party packages — covering transitive dependencies, lock files, SRI hashes, CVE scanning, and supply chain attack vectors.
CWE-1357 OWASP A6:2021
1mo ago
security intermediate
Image Optimisation
Reducing image file size and delivery overhead through format choice (AVIF, WebP), compression, responsive sizing (srcset), lazy loading, and explicit dimensions — the single highest-impact performance lever for most websites.
1mo ago
performance intermediate
Largest Contentful Paint (LCP)
A Core Web Vital that measures when the largest above-fold content element (typically the hero image or main heading) becomes visible — target under 2.5 seconds. The most impactful page speed metric.
1mo ago
performance intermediate
Mixed Content (HTTP on HTTPS)
When an HTTPS page loads resources (images, scripts, stylesheets) over HTTP — browsers block active mixed content and warn on passive, undermining the security of the HTTPS connection.
CWE-319
1mo ago
security intermediate
Resource Hints (preconnect, prefetch, preload)
HTML link attributes that instruct the browser to take early action on resources — opening connections, fetching future pages, or loading critical assets before they are discovered in HTML parsing.
1mo ago
performance intermediate
Script Loading (defer, async, type=module)
How and when browser downloads and executes JavaScript — defer, async, and type=module control whether scripts block HTML parsing and in what order they run.
1mo ago
frontend intermediate
Structured Data — JSON-LD
Machine-readable schema markup embedded in a <script type='application/ld+json'> block, enabling Google rich results — star ratings, FAQs, breadcrumbs, events, and recipes in search.
1mo ago
frontend intermediate
API Versioning
Strategies for evolving an API without breaking existing consumers — URI versioning, header versioning, and content negotiation.
2mo ago
api_design intermediate
CSS Cascade Layers (@layer)
CSS @layer lets you explicitly define the order in which style groups are applied in the cascade — styles in a later layer always win over earlier ones regardless of specificity, eliminating specificity wars in large codebases.
2mo ago
frontend intermediate
Docker HEALTHCHECK
A Dockerfile instruction that defines how Docker tests whether a container is healthy — enabling automatic restart and load balancer removal on failure.
2mo ago
devops intermediate
Git Rebase vs Merge
Merge preserves branch history with a merge commit — rebase rewrites commits onto the target branch for a linear history.
2mo ago
git intermediate
HTTP Content Negotiation
The HTTP mechanism by which clients declare what formats, languages, and encodings they accept (Accept, Accept-Language, Accept-Encoding) and servers respond with the best match — or 406 Not Acceptable if none fits.
2mo ago
api_design intermediate
HTTP/2 Server Push & Early Hints
HTTP/2 Server Push lets a server proactively send assets (CSS, JS, fonts) before the browser requests them. 103 Early Hints is its practical successor — sending Link preload headers before the full response is ready.
2mo ago
networking intermediate
INSERT ... ON DUPLICATE KEY UPDATE PHP 5.1+
An atomic MySQL upsert — inserts a new row or updates the existing one if a unique key constraint would be violated.
2mo ago
database intermediate
MySQL Connection Pooling PHP 5.1+
Reusing database connections across requests instead of opening and closing a new connection on every request.
2mo ago
php intermediate
MySQL EXPLAIN
A MySQL query analysis command showing the execution plan — which indexes are used, how many rows are scanned, and where bottlenecks are.
2mo ago
database intermediate
MySQL FULLTEXT Search
A built-in MySQL search engine supporting natural language and boolean full-text queries on TEXT and VARCHAR columns.
2mo ago
database intermediate