Injection prevention guide

validator.js is a JavaScript string validation and sanitization library. It provides a set of functions to verify that strings match specific patterns—such as emails, URLs, and alphanumeric formats—and a toolkit for cleaning and transforming text input to remove prohibited characters and trim whitespace. The library includes utilities for standardizing email addresses by lowercasing domains and removing sub-addressing markers. It also functions as an HTML entity escaper, replacing special characters with entities to prevent the browser from executing text as code. The project covers capabili

DOMPurify is a security-focused library designed to sanitize untrusted HTML input, preventing cross-site scripting attacks by stripping malicious code while preserving safe content. It functions as a utility for secure document object model manipulation, ensuring that user-provided rich text can be rendered safely within web applications. The library distinguishes itself through a single-pass, mutation-observer-free processing model that operates on detached document fragments to avoid triggering unintended side effects. It employs recursive node traversal and context-aware logic to inspect a

The OWASP Cheat Sheet Series is a comprehensive, community-driven repository of concise security best practices and defensive coding patterns. It serves as a centralized knowledge base for developers and security professionals, providing actionable guidance to secure applications across the entire software development lifecycle. The project covers a vast array of security domains, ranging from fundamental web application hardening and authentication protocols to specialized controls for modern infrastructure and artificial intelligence systems. What distinguishes this project is its decentral

Templ is a type-safe HTML templating engine and UI framework for Go. It provides a system for building reusable HTML components that compile into Go code for server-side rendering, ensuring type safety and compile-time validation of data and logic. The project features a dedicated language server that provides autocomplete and syntax validation for template files within supported code editors. It employs compile-time code generation to transform a custom template language into Go source code, enabling the creation of modular HTML fragments and logic blocks. The framework includes automated s

Joi is a JavaScript data validation library used to define schemas that validate, cast, and sanitize data objects. It functions as an object schema validator and parser, ensuring that input data matches specific types and formats before it is processed by an application. The library features a conditional validation engine capable of dynamic schema enforcement, where validation logic and dependencies change based on the values of other keys within an object. It also serves as a data casting and sanitization tool, transforming input values into target types and removing sensitive keys from the

bluemonday is a Go library for scrubbing user-generated HTML content to prevent cross-site scripting and other injection attacks. It functions as an HTML policy engine and sanitizer that removes dangerous scripts and malicious tags by applying configurable element and attribute allowlists. The project distinguishes itself through a rule-based system that utilizes regular expressions and name-based lists to define permitted tags, attributes, and CSS styles. It includes a URL security validator that enforces safe protocols and automatically injects security attributes such as nofollow and noope

art-template is a JavaScript templating engine and HTML template compiler that transforms custom syntax and script statements into optimized HTML output. It functions as a precompiled template engine that converts template source into standalone JavaScript functions to render dynamic content from data. The engine features a template inheritance framework that organizes layouts through nesting, blocks, and inclusions to create reusable components across multiple files. It incorporates automatic output sanitization and encoding to prevent cross-site scripting attacks. The system includes capab

Validator.js is a library of pure, stateless functions designed for the validation and sanitization of string data within any JavaScript environment. It provides a modular suite of tools to verify that user-provided information conforms to specific formats, such as emails, URLs, and dates, while simultaneously cleaning untrusted input to mitigate security risks. The library distinguishes itself through a design that avoids platform-specific APIs, ensuring consistent execution across browsers, servers, and edge runtimes. By utilizing a pre-compiled regular expression engine and a pure data tra

Brakeman is a static analysis security tool and scanner specifically designed for Ruby on Rails source code. It identifies common security vulnerabilities, such as injection and cross-site scripting, by analyzing the application codebase without executing the application. The tool functions as a security auditor that detects mass assignment risks and template vulnerabilities. It evaluates the final output of rendered views and identifies unrestricted assignment patterns that could allow unauthorized modification of model attributes. The system provides vulnerability management through the us

Helmet is an Express.js middleware library that sets a comprehensive collection of HTTP security headers to protect web applications from common vulnerabilities like cross-site scripting and clickjacking. At its core, it provides a configurable middleware system for injecting security headers into HTTP responses, with a primary focus on Content Security Policy configuration through custom directives and report-only testing modes. The library distinguishes itself through a flexible configuration surface that supports method chaining for composing multiple headers in a single expression, as wel

This library is a PHP framework designed for validating and sanitizing incoming data. It provides a structured approach to ensuring that information conforms to expected formats and integrity requirements before it is processed or stored by an application. The project utilizes a fluent interface to construct validation logic, allowing for the definition of complex rules through chainable methods. It employs a strategy-based execution model where individual validation components are encapsulated and can be dynamically assigned to data fields. When validation fails, the system uses an exception

FluentValidation is a strongly-typed data validation library for .NET. It functions as a rule engine and input validation framework used to define and execute complex business rules and constraints for data objects. The library utilizes a fluent interface API, allowing the construction of readable and declarative validation constraints through method chaining. It leverages generics and lambda expressions to enforce data integrity and business logic at compile time. The project covers the enforcement of business rules, strongly-typed data validation, and input sanitization workflows to verify

class-validator is a TypeScript class validation library that uses decorators to define constraints and rules for object properties. It functions as a decorator-based schema validator that ensures data integrity and structural correctness through a combination of synchronous checks and promise-based asynchronous rules. The library provides a recursive validation system for checking complex data hierarchies, including nested classes and individual elements within collections. It includes an object property whitelist utility capable of stripping undocumented properties or blocking unknown field

Sanitize is a Ruby library designed to clean untrusted HTML and CSS input by enforcing strict security policies. It functions as a web input validator and security filtering tool, processing HTML fragments or full documents to remove unauthorized elements, attributes, and dangerous code patterns that could lead to cross-site scripting or injection attacks. The library distinguishes itself through a tree-based traversal mechanism that evaluates document structures against customizable allowlists. Beyond standard filtering, it provides granular control over content by allowing developers to inj