Glossary
Unicode Fundamentals
PHP 5.0+
Unicode assigns every character a code point — UTF-8 encodes these as 1-4 bytes, making it the universal encoding for text on the web.
3mo ago
i18n intermediate
Unicode Normalisation Attack
PHP 5.3+
Exploiting differences in Unicode normalisation forms to bypass input filters — two visually identical strings that differ at the byte level.
CWE-176 OWASP A3:2021
3mo ago
security advanced
5.3
Union Types (PHP 8.0)
PHP 8.0+
Allow a parameter, return value, or property to accept multiple specified types, declared as TypeA|TypeB.
3mo ago
php intermediate
Unit of Work
A pattern that tracks all changes made to domain objects during a business transaction and coordinates writing them out as a single atomic database operation.
3mo ago
quality advanced
Unit Testing
PHP 5.0+
1
Automated tests that verify individual units of code (classes, methods) in isolation from external dependencies.
3mo ago
testing beginner
UPSERT
PHP 5.0+
An atomic INSERT-or-UPDATE operation — inserts the row if it does not exist, updates it if it does — eliminating the race condition of a separate check-then-insert.
3mo ago
database intermediate
Using AI APIs in PHP
PHP 8.0+
1
Integrating LLM APIs (OpenAI, Anthropic, Gemini) into PHP applications — for text generation, classification, extraction, and embedding-based search.
3mo ago
ai_ml intermediate
UUID vs Auto-Increment IDs
UUIDs are globally unique identifiers that don't expose record counts or enable enumeration, at the cost of larger index size and random writes.
3mo ago
general beginner
UUID vs ULID vs Auto-Increment
PHP 7.0+
Primary key strategies: auto-increment is simple and fast, UUID v4 is globally unique but random (poor index performance), UUID v7 and ULID are sortable globally unique IDs.
3mo ago
database intermediate
Value Object
PHP 8.1+
4
A small immutable object defined by its value rather than its identity — two Value Objects with the same data are equal.
3mo ago
quality intermediate
Vector Databases
Databases specialised for storing and querying high-dimensional vectors — enabling fast approximate nearest-neighbour search across millions of embeddings.
3mo ago
ai_ml intermediate
Visitor Pattern
PHP 5.0+
A behavioural pattern that separates an algorithm from the objects it operates on — adding new operations to a class hierarchy without modifying those classes.
3mo ago
quality advanced
WCAG Guidelines
Web Content Accessibility Guidelines — the international standard defining how to make web content accessible to people with disabilities, organised into three conformance levels (A, AA, AAA).
3mo ago
accessibility intermediate
Weak Cryptography
PHP 5.0+
Using MD5 or SHA1 for passwords or security tokens — both are cryptographically broken and trivially reversible.
CWE-327 OWASP A2:2021
3mo ago
security intermediate
7.5
Weak References (WeakReference, WeakMap)
PHP 7.4+
References to objects that don't prevent garbage collection — useful for caches and observer registries that shouldn't extend object lifetimes.
3mo ago
php advanced
Weak Session ID
PHP 5.0+
Session identifiers generated with insufficient entropy can be guessed or brute-forced, allowing session hijacking.
CWE-330 OWASP A2:2021
3mo ago
security intermediate
8.1
WeakMap (PHP 8.0)
PHP 8.0+
A map keyed by objects that doesn't prevent garbage collection — ideal for caching per-object computed data without creating memory leaks.
3mo ago
php advanced
Web Accessibility (WCAG & ARIA)
HTML5
Building web UIs usable by people with disabilities — following WCAG guidelines and using ARIA roles only when semantic HTML is insufficient.
3mo ago
frontend intermediate
Web Cache Deception
Tricking a cache into storing sensitive authenticated responses by appending a static-file-like suffix to a private URL.
CWE-524 OWASP A5:2021
3mo ago
security advanced
7.5
Web Components
ES2018
A suite of native browser APIs (Custom Elements, Shadow DOM, HTML Templates) for creating reusable, encapsulated HTML elements without frameworks.
3mo ago
frontend advanced