Terms starting with "I"
Insecure TLS / SSL
PHP 5.0+
Use of deprecated SSL/TLS versions or weak cipher suites exposes encrypted traffic to interception or decryption attacks.
CWE-326 OWASP A2:2021
6mo ago
Security intermediate
7.4
Integration Testing
PHP 5.0+
3
Tests that verify multiple components work correctly together — often involving real databases, HTTP clients, or third-party services.
6mo ago
Testing intermediate
Interface Segregation Principle
Clients should not be forced to depend on interfaces they do not use — prefer many small, focused interfaces over one large one.
6mo ago
Code Quality intermediate
Interface vs Abstract Class
PHP 5.0+ Interfaces define pure capability contracts with no state; abstract classes add shared implementation. Use interfaces for type contracts, abstract for shared behaviour.
6mo ago
PHP intermediate
Interfaces
PHP 5.0+
3
Contracts that define a set of method signatures a class must implement, enabling polymorphism without inheritance.
6mo ago
PHP intermediate
Intersection Observer API
ES2015
A browser API that efficiently detects when elements enter or leave the viewport — replacing scroll event listeners for lazy loading, infinite scroll, and animation triggers.
6mo ago
Frontend intermediate
Intersection Types (PHP 8.1)
PHP 8.1+
1
Require a value to satisfy multiple type constraints simultaneously, declared as TypeA&TypeB — useful for combining interfaces.
6mo ago
PHP intermediate
intval() / Type Casting
PHP 5.0+
1
Casting user input to int or float is a safe way to enforce numeric types — cheaper than regex validation for IDs.
6mo ago
PHP beginner
IPv6 for Web Developers
The successor to IPv4 with 128-bit addresses — effectively unlimited address space, mandatory in modern infrastructure, with some practical differences for web applications.
6mo ago
Networking intermediate
Iterator Pattern
PHP 5.0+
Provides a uniform way to traverse a collection without exposing its internal structure — the foundation of PHP's foreach and SPL iterators.
6mo ago
Code Quality intermediate
Iterators & IteratorAggregate
PHP 5.0+
1
PHP interfaces that allow custom objects to be used in foreach loops, enabling lazy and memory-efficient iteration over any data source.
6mo ago
PHP intermediate
Immutability
PHP 8.1+
3
Objects whose state cannot change after construction — immutable objects are inherently thread-safe, predictable, and easy to reason about.
7mo ago
Code Quality intermediate
Input Validation vs Output Encoding
PHP 5.0+
5
Validation checks that input is acceptable; output encoding makes data safe for the context it's rendered in. Both are required.
7mo ago
General beginner
Insecure Direct Object Reference (IDOR)
PHP 5.0+
1
A user accesses another user's data by changing an ID in a URL or request — no authorisation check performed.
CWE-639 OWASP A1:2021
7mo ago
Security intermediate
7.5
Insufficient Logging & Monitoring
Failure to log security events and monitor them allows attacks to go undetected and unresponded to.
CWE-778 OWASP A9:2021
7mo ago
Security beginner
6.5