Opcache¶
OPcache improves PHP performance by storing precompiled script bytecode in shared memory, thereby removing the need for PHP to load and parse scripts on each request.
Related : Opcode
The definitive reference with all things PHP, and their definitions.
Navigation
Contents:
- Introduction
- Index
- $_COOKIE
- $_ENV
- $_GET
- $_POST
- $_REQUEST
- $_SERVER
- $argc
- $argv
- $GLOBALS
- $http_response_header
- $php_errormsg
- $this
- __autoload
- __call() Method
- __callStatic() Method
- __CLASS__
- __clone() Method
- __FILE__
- __FUNCTION__
- __get() Method
- __invoke() Method
- __isset() Method
- __LINE__
- __METHOD__
- __serialize() Method
- __set() Method
- __set_state() Method
- __sleep() Method
- __toString() Method
- __TRAIT__
- __unserialize() Method
- __unset() Method
- __wakeup() Method
- abs()
- Absolute Name
- Absolute Value
- Absolute
- Abstract Class
- Abstract Factory
- Abstract Method
- Abstract Keyword
- Abstraction Layer
- Abstraction
- Accessibility
- Accountability
- Active Record
- Adapters
- Addition
- Architectural Decision Record (ADR)
- Agile
- Algorithm
- Algorithmic Complexity
- Alias Types
- Alias
- Allow Dynamic Properties
- Alternative Syntax
- And Operator
- Annotations
- Anonymize
- Anonymous Catch
- Anonymous Class
- Anonymous Constant
- Anonymous Function
- Anonymous
- Ahead Of Time (OAT)
- Application Programming Interface (API)
- Application Performance Management (APM)
- Application Server
- Array Append
- Arbitrary Number Of Argument
- Arcane
- Architecture
- Archive
- Argon2
- Argument
- ArgumentCountError
- ArithmeticError Error
- Arm
- Callable Arrays
- Array Callback
- Array With Curly Braces
- Array Element
- Array Spread
- Array Syntax
- Array
- array_column
- array_combine()
- array_key_exists()
- array_keys()
- array_map()
- array_merge()
- array_unique()
- array_values()
- array_walk()
- ArrayAccess
- ArrayObject
- Arrow Functions
- Artifact
- As
- American Standard Code for Information Interchange (ASCII)
- Aspect Oriented Programming
- Assertions
- Asset
- Assignations
- Associative Array
- Assumption
- Abstract Syntactic Tree (AST)
- Asymmetric Property
- Asymmetric Visibility
- Async
- Asynchronous
- Attribute Class
- Attribute
- Audit Trail
- Authentication
- Authorize
- Preappend File Directive
- Class Autoloading
- Automagic
- Automatic Index
- Autovivification
- Autowiring
- Backslash
- Backed Enum
- Backed Property
- Backed
- BackedEnum
- Backend
- Back-tick
- Backtrace
- Backward Incompatible
- BadFunctioncallException
- Balanced
- Bang !
- Base 64 Encoding
- basename
- Batch
- Bcmath
- Benchmarking
- Best Practices
- Binary Integer
- Binary Not Operator
- Binary Operator
- Binary
- Bind
- Bitfield
- Bitmask
- Bitshift Operators
- Bitwise Operators
- Blind Variable
- Block
- Bloom Filter
- Body
- Boilerplate
- Broken Object Level Authorization (BOLA)
- Boolean
- Bootstrap
- Bottleneck
- Bracket
- Bracketless
- Branch
- Breach
- Break
- browscap
- Bucket
- Bug
- Passing By Reference
- Passing By Value
- Byte
- bzip2 Extension
- C2 Framework
- Cache
- Calendar
- Call
- Callables
- Callbacks
- Callstack
- Camel Case
- Canonical
- CAPTCHA
- Case Sensitivity
- Case
- Cast Operator
- Catch
- Continuous Delivery (CD)
- Centralization
- Common Interface Gateway (CGI)
- Chaining New Without Parenthesis
- Chaining
- Character
- Child Class
- Continuous Integration (CI)
- Circuit Breaker
- Circular Reference
- Class Interface Trait Enumeration (CITE)
- Class Aliases
- Class Constant Syntax
- Class Constants Visibility
- Static Constant
- Class Entities
- Class Hierarchy
- Class Hoisting
- Class Invasion
- Class Operator
- Class
- class_alias()
- Clean Architecture
- Clean Code
- Command Line Interface (CLI)
- Clone
- Close Naming
- Close Tag
- Closed Source
- ClosedGeneratorException
- Closure Binding
- Closure Class
- Closure
- Content Management System (CMS)
- Coalesce Operator
- Code Architecture
- Code Coverage
- Code Formatter
- Coding Formatting
- Code Freeze
- Code Generator
- Code Injection
- Code Reuse
- Code Review
- Code Smell
- Codepoint
- Coding Conventions
- Cognitive Complexity
- Collection
- Collision
- Colon
- Comma
- Command Bus
- Comments
- Commit
- Community
- Compact Array
- compact()
- Comparison
- Compatibility
- Compile Time
- Compile
- Complexity
- Compliance
- Component
- Composer
- Composition
- Compression
- Concatenation
- Concatenative
- Concrete Method
- Concrete Class
- Concurency
- Condition
- Conditional Structures
- Conditioned Structures
- Configuration
- Connexion Persistence
- Consistency
- Const
- Constant Case
- Constant Combinaison
- Constant Expression
- constant()
- Constants In Trait
- Constant Scalar Expression
- Constants
- Constructor
- Container
- Continue
- Design By Contract (DBC)
- Control Flow Graph
- Control Flow
- Control Structures
- Controller
- Convention
- Convert
- Cookie
- Copy On Write (COW)
- Core
- Coroutine
- count()
- Countable Interface
- Coupling
- Coverage
- Command Query Responsibility Segregation (CQRS)
- Cyclic Redundancy Check 32-bit (CRC32)
- Cron
- Create, Read, Update And Delete (CRUD)
- To Crypt
- Cryptography
- Cross Site Request Forgery (CSRF)
- CSV Injection
- Comma Secparated Values (CSV)
- Ctype
- Client URL (CURL)
- Curly Brackets
- Custom
- Common Vulnerabilities And Exposures (CVE)
- Concurent Version System (CVS)
- Cyclomatic Complexity
- Dangling Reference
- Data Access Object (DAO)
- Data Container
- Data Leak
- Data Mapper
- Data
- Database
- Dataset
- Datastack
- Dates
- DateInterval
- Datetime Trap
- DateTime
- Day Are Not 86400 Seconds
- Days In Month
- Database Abstraction Layer (DBA) Extension
- Database Abstraction Layer (DBAL)
- Domain Design Driven (DDD)
- Distributed Denial Of Service (DDOS)
- Dead Code
- Technical Debt
- Debugger
- Declaration
- Declarative Programming
- declare Encoding
- declare()
- Decorator Pattern
- Decoupling
- To Decrypt
- Deep Clone
- Default Parameter
- Default Value
- Default
- default_charset
- Defensive Programming
- define()
- defined()
- Definition
- delayedtargetvalidation
- Delimiter
- Dependency Injection Container
- Dependency Injection
- Dependency
- Dependent Type
- Deployment
- Deprecated
- Deprecation
- Depth
- Dereferencing
- Design Pattern
- Destructor
- Dictionary
- Diff
- Dir
- Directives
- DIRECTORY_SEPARATOR
- DirectoryIterator
- dirname
- Disable Classes
- Disable Functions
- Disable
- display_errors
- Division
- DivisionByZeroError
- Disjunctive Normal Form (DNF)
- Domain Name System (DNS)
- Do While
- Docblock
- Docker Container
- Documentation
- Dollar /
- DomainException
- DOM
- . Directory
- . File
- Dot Notation
- Double Arrow
- Double Check
- Double Quotes Strings
- Double
- Downtime
- Don’t Repeat Yourself (DRY)
- Data Structure
- Data Source Name (DSN)
- Data Transfer Object (DTO)
- Duck Typing
- Dynamic Call
- Dynamic Class Constant
- Dynamic Class
- Dynamic Constant
- Dynamic Expression
- Dynamic Loading
- Dynamic Method
- Dynamic Properties
- Dynamic Variable
- Dynamic
- each
- Early Binding
- Echo Tag
- Echo
- Ecosystem
- Edge Case
- Elephpant
- Ellipsis
- Embed
- Emoji
- Empty String
- Empty
- Enable
- Encapsulation
- Text Encoding
- Encoding
- PHP Engine
- Entities
- Enumeration Case
- Enumeration (enum)
- .env File
- Environment Variables
- Environment
- Eponymous
- Equal Operator
- Error Handler
- Error Handling
- Error Reporting
- Error
- Error Reporting
- Escape Character
- Escape Data
- HTML Escaping
- Escape Sequences
- Eval()
- Event Driven
- Event Loop
- Event Sourcing
- Event Storming
- Chaining Exceptions
- Exception Handler
- Exception
- exec
- Execution Path
- Execution Time
- Exit
- Explicit Boolean Comparison
- Explicit
- explode()
- Exponent
- Exponential
- expose_php
- Expression
- Expressive Interface
- extends
- Extensions
- extract()
- Facade
- Factory
- Faker
- Fallback Function
- Fallback To Global
- Switch Fallthrough
- False
- Falsy
- FastCGI
- Fatal Error
- Feature Flag
- Feature Testing
- Feature
- Foreign Function Interface (FFI)
- Fibers
- First In, First Out (FIFO)
- File Extension
- File Mode
- File
- file_get_contents()
- file_put_contents()
- File System
- FileSystemIterator
- filter
- Final Class Constants
- Final Keyword
- Finally
- Finite State Machine
- First Class Callable
- Fixture
- Flag
- Flame Graph
- Floating Point Numbers
- Fluent Interface
- fnmatch()
- Folklore
- For
- foreach()
- Form
- Format
- Forum
- Forward Compatible
- Fossilized Methods
- FastCGI Process Manager (FPM)
- Framework
- Front-end
- File Transfer Protocol (FTP)
- File Transfer Protocol Secure (FTPS)
- Fully Qualified Name
- func_get_args()
- Function Subscripting
- Functions
- Functional Programming
- Functor
- Fuzzing
- Garbage Collection
- Graphic Draw (GD)
- Generator
- Generics
- get_class()
- get_object_vars()
- Class Getter Method
- gettext Extension
- git
- glob()
- Global Code
- Global Space
- Global Variables
- global Scope
- $GLOBALS
- Glue
- GNU Multiple Precision (GMP)
- God Object
- Golf
- Goto
- Gradual Type Checking
- GraphQL
- gRPC (Google Remote Procedure Call)
- __halt_compiler()
- Handle
- PHP Handlers
- Hard Coded
- Hardening
- Hash #
- Hash Comparisons
- Cryptographic Hash
- hash() Function
- Hash
- Haystack
- Headless
- Heredocs
- Heuristics
- Hexadecimal Integer
- Hexagonal Architecture
- hg
- Honey Pot
- Hosting
- hrtime()
- .htaccess
- HTML Entities
- HTML Entity
- HyperText Markup Language (HTML)
- html_errors
- HTTP Code
- HTTP Encoding
- HTTP Headers
- Hyper Text Transfer Protocol (HTTP)
- http_build_query()
- Hyper Text Transfer Protocol Secure (HTTPS)
- Hydratation
- Iconv
- Idempotent
- Identical Operator
- Identification
- Identifier
- Identity Comparison
- If Then Else
- Iffectation
- Image
- imagick
- ImagickException
- ImagickPixelException
- Immutable
- Imperative Programming
- implements
- Implicit
- implode()
- Import
- in_array()
- include
- include_path
- Inclusions
- Incoming Data
- Increment
- Indentation
- Index For Arrays
- Index For SQL
- Index
- Indexed Array
- Inequality
- INF
- Infinite Loop
- Infinite
- InfiniteIterator
- Inflector
- Inheritance
- Inherited Variable
- INI
- ini_set()
- Initialisation
- Injection
- Inlining
- instance
- instanceof
- Insteadof
- integer
- Interface
- Internals
- Internationalization
- Interpolation
- Intersection Type
- Internationalization Functions
- InvalidArgumentException
- Type Invariant
- Code Inventory
- Invoke
- Internet Protocol (IP)
- is_a()
- is_object()
- Interface Segregation Principle (ISP)
- Isset
- Iterable
- Iterator
- iterator_to_array()
- IteratorAggregate
- Javascript
- Just In Time (JIT)
- Jobqueue
- JavaScript Object Notation (JSON)
- json_decode()
- json_encode()
- JSON Lines (JSONC)
- JsonException
- JSON Lines (JSONL)
- JsonSerializable
- Jump
- Key-value Stores
- Keyword
- KISS
- Goto Labels
- Linux Apache Mysql PHP (LAMP)
- Language Construct
- Laravel
- Late Static Binding
- Latin1
- Lazy Loading
- Lazy Objects
- Leading Numeric String
- Leading Zero Means Octal
- Leak
- LengthException
- Letter Logical Bug
- Lexical Variable
- Library Loading
- libsodium
- Licence
- Lifecycle
- Last In, First Out (LIFO)
- Line Feed
- Lint, Won’t Execute
- Linting
- List
- Literal Types
- Literal
- Large Language Model (LLM)
- Local File Inclusion
- Local Variable
- Local Scope
- Locale
- Lock
- Log
- Logical Operators
- LogicException
- Loops
- Liskov Substitution Principle (LSP)
- Machine Learning
- Magic Bytes
- Magic Constants
- Magic Hash
- Magic Code
- Magic Methods
- Magic Numbers
- Magic Property
- Magic
- Maintenability
- Maintenance
- Man In The Middle
- Map
- Markdown
- Marketplace
- Match
- Math
- max_execution_time
- Multibyte String
- Model Context Protocol (MCP)
- mcrypt Extension
- Message Digest Algorithm 5 (MD5)
- Memoization
- Memory Leak
- Memory
- memory_limit
- Merge
- Message Queue
- Method Collision
- Method Compatibility
- Method Overloading
- Method
- Methodcall
- Metrics
- Micro-optimisation
- Micro-second
- Micro-framework
- Microservice
- microtime()
- Middleware Pattern
- Migration
- Minification
- Minus One -1
- Minus -
- Missing Validation
- Mixed
- Mock
- Model
- Module
- Modulo
- Monitoring
- Monolith
- Multi-byte
- Multidimensional Array
- Multiplication
- Multithreading
- Multiton
- Mutation Testing
- Model - View - Controller (MVC)
- Minimum Viable Product (MVP)
- MySQL
- mysqli
- mysqli_sql_exception
- N+1 Query Problem
- Name
- Named Constructors
- Named Parameters
- Named Type
- Namespace Alias
- Namespace Name
- Namespaces
- Namespaced Name
- Naming Conflict
- Naming
- Not A Number (NAN)
- PHP Natives
- Native
- Needle
- negative-index
- Nested Attributes
- Nesting
- Neutral Element
- Never Type
- New In Initializers
- New Line
- New Without Parenthesis
- new
- NoDiscard
- Non Breakable Spaces
- Non-instantiable
- Non-numeric
- Non-static
- Nonce
- Noop
- @, No Scream Operator
- Nosql Database
- Not Operator
- Notice
- Nowdocs
- Null Byte
- Null
- Nullable
- Null Pattern
- Null Safe Object Operator
- Nullsafe
- Number
- Numeric Base
- Numeric Separator
- Numeric String
- Obfuscation
- Object API
- Object Injection
- Object Invasion
- Object Nullsafe Operator ?->
- Object Operator ->
- Object Persistence
- Object Syntax
- Object Type
- Object
- Oblic Quotes
- Observer Design Pattern
- Open Closed Principle (OCP)
- Octal Integer
- Offensive Programming
- Offset
- One Liner
- one
- Onion Architecture
- OOP (Object Oriented Programming)
- Opcache
- Opcode Specialisation
- Opcode
- Open Source
- Open Tag
- open_basedir
- OpenSSL
- Operand
- Operator Overloading
- Operator Precedence
- Operators
- Optimisation
- Optional Parameter
- Object Relational Mapping (ORM)
- Outgoing Data
- OutOfRangeException
- Over-engineer
- Overflow
- OverflowException
- Overloading
- Override Attribute
- Overriding
- Overwrite
- OWASP
- pack
- Packagist
- Pagination
- Paradigm
- Parallel
- Parameter Removal
- Parameter
- parent
- Parenthesis
- Parquet
- Parse
- parse_str()
- ParseError
- Parser
- Partial Function
- Pascal Case
- Passphrase
- Password API
- Password
- Path Traversal
- Path
- Pattern Matching
- Process Control (pcntl)
- Perl Compatible Regular Expressions (PCRE)
- PHP Data Objects (PDO)
- PDOException
- Product Requirements Document (PDR)
- PEAR
- PHP Extension C Library (PECL)
- Performance
- Permission
- Persistence
- PostgreSQL
- Phar
- PharException
- PHP Native Attributes
- PHP Constants
- PHP Docker Container
- PHP Engine
- PHP Extensions
- Framework Interoperability Group (FIG)
- PHP Foundation
- PHP Group
- php://input
- PHP Native Interfaces
- php://memory
- PHP Native Attribute
- php://output
- PHP RFC
- PHP Tags
- PHP User Groups
- PHP Variables
- PHP Wrappers
- PHP, Hypertext Preprocessor (PHP)
- php.ini
- PHP_INT_MAX
- PHP_INT_MIN
- PHPdoc
- phpinfo()
- PHPunit
- PHP Installer For Extensions (PIE)
- Pipe Operator
- Pipe Operator
- Pipeline
- Plugin
- Plus +
- Pointer
- Polyfill
- Polymorphism
- Port
- Portability
- Positional Parameters
- Positive Integer
- Post-increment
- Pull Request (PR)
- Pre-increment
- Precedence
- precision
- Predefined Constants
- PHP Predefined Exception
- Prefix
- Preg_match
- preg_split()
- Prepared Query
- Array Prepend
- Preprocessing
- Primitive Obsession
- print_r()
- printf()
- Private Visibility
- Procedural Programming
- Process
- Production
- PHP Profiler
- Promise
- Promoted Properties
- Propagation
- Property Hook
- Properties
- Protected Visibility
- Protocol
- Pseudo-type
- Pseudo-variable
- PHP Standards Recommendations (PSR)
- Public Visibility
- Pure Function
- Quality
- Query String
- Query
- Question Mark ?
- Queue
- Quine
- Quoted Printable
- Retrieval Augmented Generation (RAG)
- Railroad Programming
- Random
- range()
- RangeException
- Role Based Access Control (RBAC)
- Remote Code Execution (RCE)
- Relational DataBase Management System (RDBMS)
- Readability
- Readable
- Reading
- Readline
- Readonly
- Real Time
- Real Numbers
- Recursion
- Recursive Array
- RecursiveIterator
- RecursiveTreeIterator
- Refactoring
- Reference Count
- References
- Reflection
- ReflectionException
- Regular Expressions
- Regexploit
- Register Globals
- register_argc_argv
- Registry
- Relative Name
- Relative Types
- Relative
- Relaxed Comparison
- Relaxed Keywords
- Relaxed Syntax
- Relay Function
- Release
- Render
- Renderer
- Read Eval Print Loop (REPL)
- Reserved Names
- resource
- REST API
- Return Carriage
- Return Type
- Return Value
- Return
- Return Type Will Change
- Revision
- RFC
- Request For Change (RFC)
- Reserved For Future Use (RFU)
- Rounding
- Route
- Remote Procedure Call (RPC)
- RSA
- Rubber Ducking Debugging
- Runtime Checks
- Software-as-a-Service (SAAS)
- Sandbox
- Sanitation
- Server Application Programming Interface (SAPI)
- Static Application Security Testing (SAST)
- Software Bill Of Material (SBOM)
- Static Code Analysis (SCA)
- Scaffolding
- Scalar Types
- Scaling
- Schema
- Scheme
- Scope Resolution Operator ::
- Scope
- Software Development Kit (SDK)
- Software Development Life Cycle (SDLC)
- Second Order SQL Injection
- Secret
- Security
- Segmentation Fault
- Self-documenting
- Self-reference
- Self
- Semantic Versioning
- Semantics
- Semicolon
- Sensitive Parameter
- Separator
- Serde
- Serializable
- Serialization
- Server Architecture
- Service Container
- Service
- Session Fixation
- Session Hijacking
- Session
- set_error_handler()
- Class Setter Method
- Secure Hash Algorithm (SHA)
- Shallow Clone
- Shard
- Shared Memory
- Shell
- shell_exec()
- Short Assignations
- Short Syntax
- Short Tags
- Short Ternary Operator
- Shutdown Function
- Side Effect
- Sign
- Method Signature
- Silent Behavior
- Simple Switch
- SimpleXML
- Single Quotes Strings
- Singleton
- Slash /
- sleep
- Simple Mail Transfer Protocol (SMTP)
- Snake Case
- Simple Network Management Protocol (SNMP)
- SNMP3
- Simple Object Access Protocol (SOAP)
- Socket
- SOLID
- Sort
- Single Page Application (SPA)
- Space
- Spaceship Operator
- Special Constant
- Special Types
- Standard PHP Library (SPL)
- SplDoublyLinkedList
- SplStack
- SplStorageObjects
- sprintf
- SQL Database
- SQL Injection
- Simple Query Language (SQL)
- Sqlite3
- Square Brackets
- Single Responsability Principle (SRP)
- Static Single Assignment Form (SSA)
- Server Sent Event (SSE)
- Secure Sockets Layer (SSL)
- Single Sign On (SSO)
- Stack
- Standalone Types
- Star *
- State
- Stateful
- Stateless
- Statement
- Static Call
- Static Expression
- Static Method
- Static Property
- Static Variables
- static
- stdclass
- STDOUT
- Stealth Generator
- Storage Systems
- str_contains()
- Stream
- Strict Comparison
- strict_types
- String Increment
- String Interpolation
- String
- Stringable
- Strpos() Syndrome
- strpos
- Structure
- Stubs Files
- Sub (prefix)
- Subclass
- Subnamespaces
- subtype
- Suffix
- Sunsetting
- Superglobal Variables
- supertype
- Supply Chain Attack
- Supply Chain
- Support Vector Machine (SVM)
- SVMException
- SVN
- Swap
- Switch Case
- Switch Default
- Switch
- Synchronous
- Syntax Error
- Syntax
- System Call
- System Event
- System
- Tabulation
- Taint Analysis
- Tarpit
- Task Runner
- Task
- Total Cost Of Ownership (TCO)
- TCP
- Telemetry
- Template
- Temporary Expression
- Ternary Operator
- Test Data Provider
- Test Pyramid
- Test
- testdox
- Thin Method
- Thread
- Three Dots
- throw
- Throwable
- Tick
- ~ Tilde
- Time Travel
- Transport Layer Security (TLS)
- Time Of Check To Time Of Use (TOCTOU)
- Token
- Tom’s Obvious Minimal Language (TOML)
- Token Oriented Object Notation (TOON)
- Trailing Comma
- Trait
- Transpile
- Traversable
- Traversal
- Tree
- Treemap
- trigger_error()
- trim
- Troubleshoot
- True
- Truthy
- Try-catch
- Tutorial
- Contravariance
- Covariance
- Type Coverage
- Property Type Declaration
- Type Juggling
- Type System
- Typed Constant
- Typed Property
- TypeError
- Type Error
- Typo
- User Datagram Protocol (UDP)
- Unary Operator
- Unbacked Enum
- Undefined
- Underflow
- Underscore
- UnexpectedValueException
- UnhandledMatchError
- Unicode
- Uninitialized
- Union Type
- UnitEnum
- Unpacking
- Unreachable Code
- Unserialization
- unset()
- Unused
- User Operations For Zend (UOPZ)
- Upgrade
- File Upload
- URI Class
- URI Extension
- Universal Resource Identifier (URI)
- Universal Resource Locator (URL)
- Use Alias
- Use In Traits
- Use
- Used
- Useless
- Userland
- UTF-8
- UUencode Encoding
- Universally Unique IDentifier (UUID)
- Validation
- Value Object
- Value
- ValueError
- Var
- var_dump()
- Variable Arguments
- Variable Scope
- Variable Shadowing
- Variable Variables
- Variables
- variable_order
- Variadic
- VCS
- Vector Database
- Vendor Lock-in
- Version
- View In Presentation
- SQL Views
- View
- Virtual Machine (VM)
- Virtual Property
- Visibility
- Visual Debt
- Value Object (VO)
- (void) Cast
- Void
- Vulnerability
- Warning
- Weak Cryptography
- Weak References
- Weakmap
- Web-spider
- World Wide Web (WWW)
- WebRTC
- Webscraping
- Webserver
- Webshell
- Websocket
- Write Everything Twice (WET)
- While
- Whitespace
- Wildcard
- Class Wither Method
- Word Combination
- Workflow
- Design Pattern Wrapper
- file://
- ftp://
- http://
- Wrapper Pattern
- php://
- Stream Wrapper
- Wrapper
- Writable
- Writing
- XML Database
- Extensible Markup Language (XML)
- XMLReader
- XMLwriter
- Cross Site Scripting (XSS)
- XXTEA
- You Are Not Going To Need It (YAGNI)
- YAML Ain’t Markup Language (YAML)
- yield from Keyword
- Yield
- Yoda Condition
- zend.assertions
- Zend Engine
- Zero Cost
- zero
- zip Extension
- zlib extension
- Zombie Code
- Zval
- Thesaurus
- PHP Dictionary