Open-source alternatives to Validator

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

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

This library is a declarative validation framework for Rust that enforces data integrity and business rules on structured data models. It utilizes procedural macros to transform attribute-based annotations into executable validation logic, ensuring that data structures adhere to defined constraints before processing. The framework distinguishes itself by performing validation at compile time, which eliminates runtime overhead and provides strict type checking for all rules. It supports recursive traversal of nested data structures and collections, ensuring that every level of a hierarchy is v

This project is a protocol buffer validation plugin and code generator that creates consistent validation logic across multiple programming languages. It functions as a compiler extension for the Protocol Buffer toolchain, allowing developers to define semantic constraints directly within schema files to ensure data consistency. The tool uses custom options to embed validation rules into message definitions, mapping these schema constraints to language-specific implementation patterns. It employs predicate-based constraint checking and recursive traversal to enforce rules across nested messag

Instructor is a framework designed for structured data extraction, validation, and language model integration. It functions as a library that transforms unstructured text into validated, type-safe objects by leveraging schema definitions and model-specific tool-calling capabilities. By acting as a validation middleware, the project ensures that language model outputs strictly conform to defined data structures. The library distinguishes itself through a robust validation-based retry loop that automatically re-submits failed responses with error feedback to iteratively correct schema complianc

This is a Go library for reading and writing XLSX files, providing a toolkit for spreadsheet generation and data extraction. It functions as an Office Open XML parser and generator, enabling the creation of workbooks with support for styles, formulas, and metadata. The project features a data mapper that uses Go struct tags and reflection to automatically align spreadsheet rows with structured data. It also includes a validation engine for defining input constraints, such as dropdown lists and error alerts, to control user data entry. The library covers a broad range of capabilities, includi

env is a Go library that reads environment variables and populates the fields of a Go struct according to tag directives. It uses reflection to iterate over struct types and tags at runtime, mapping environment variable names to struct fields and applying parsing behavior defined in struct tags. The library supports required field validation, returning errors when marked fields are missing or empty after parsing. It also provides default value fallback from struct tags when environment variables are not set, environment variable expansion that recursively substitutes references within values,

xorm is a relational mapper and object-relational mapping tool for Go. It translates Go structures into SQL queries and maps database rows back into native objects, providing a multi-dialect database driver that supports MySQL, PostgreSQL, SQLite, Oracle, SQL Server, and TiDB. The project features a read-write splitting manager that routes modification requests to a primary database and read requests to replicas. It includes a database schema synchronizer to automatically align table structures and indexes with application data models, as well as a fluent SQL query builder for constructing co

mapstructure is a reflection-based library for the bidirectional encoding and decoding of generic map data into native typed Go structures. It functions as a tool for transforming loosely typed map values into specific structs and encoding those structs back into maps. The library utilizes Go reflection to map generic data keys to struct fields during runtime. It supports the transformation of untyped data from dynamic sources or configuration files into type-safe native structures. The mapping process includes recursive traversal of nested maps and slices, as well as the use of struct tags

Bun is a type-safe object relational mapper for Go that prioritizes SQL-first query construction and result mapping. It functions as a programmable SQL query builder, a database connection manager, and a tool for mapping database tables to Go structs. The project distinguishes itself through a multi-dialect SQL support system, allowing a single codebase to interact with different database engines via a consistent interface. It includes a built-in database observability tool for query interception, distributed tracing, and logging, as well as a schema migration tool for versioning structural c

Kong is a declarative command line interface framework and parser for Go. It maps flags and positional arguments directly into typed Go structures using struct tags, allowing developers to define terminal interfaces through data models rather than manual parsing logic. The project functions as a configuration mapper that populates Go structures from a combination of command-line arguments, environment variables, and JSON files. It distinguishes itself by providing a dependency injection container to pass external services into command handlers and a plugin architecture for dynamic command reg

envconfig is a Go configuration decoder and environment variable mapper that deserializes environment variables into structured Go data types. It provides tools for validating mandatory fields and ensuring application configuration adheres to the external configuration patterns of twelve-factor app compliance. The library features a help generator that creates formatted usage text based on struct definitions to describe expected environment variables. It also includes a validation tool capable of detecting unused environment variables that match a specific prefix but do not correspond to any

React Hook Form is a state management library designed to handle form registration, validation, and submission lifecycle events. By decoupling form control logic from the standard component lifecycle, it enables the creation of performant forms that minimize unnecessary re-renders. The library integrates with external schema validation tools to enforce data integrity and provides a declarative framework for managing complex form structures. The project distinguishes itself through a subscription-based architecture that tracks property access to ensure components only update when the specific

This library is a PHP framework for enforcing data integrity and business rules by validating scalar values and complex object structures against predefined constraints. It provides a structured approach to inspecting object graphs and property metadata, ensuring that data conforms to expected requirements before it is processed by an application. The framework distinguishes itself through a metadata-driven mapping system that uses reflection or configuration files to apply rules directly to object properties. It supports contextual rule orchestration, allowing developers to organize constrai

This repository serves as a comprehensive collection of reference implementations for the Remix web framework. It provides practical examples of full-stack web development, demonstrating how to build dynamic, server-rendered applications that bridge server-side logic with client-side interactivity. By leveraging a component-based architecture, these examples illustrate core patterns for managing data, routing, and user interfaces within a unified development environment. The collection highlights the framework's distinctive approach to web architecture, emphasizing server-side data loading an

NaughtyAttributes is a collection of custom attributes for the Unity Editor inspector that allows for field validation, the exposure of non-serialized properties, and the addition of custom UI controls. It functions as an extension library to customize how fields are drawn and behave within the inspector interface without requiring the author to write custom editor scripts. The library provides tools for creating interactive elements such as buttons that execute specific methods, as well as specialized input controls like sliders and dropdowns. It enables the display of native properties and

This library provides a framework for defining typed, immutable data structures in PHP. It enables developers to construct structured objects from raw input arrays, ensuring consistent data shapes and schema integrity across different layers of an application. By enforcing strict property types and validation rules during instantiation, the library prevents invalid data states and simplifies the handling of complex information. The project distinguishes itself through its use of attribute-driven metadata, which allows for property renaming, custom validation, and serialization logic directly

Marshmallow is a Python data serialization library and validation framework. It functions as a bridge that transforms complex application objects into primitive data types for storage or network transmission and vice versa. The library utilizes a schema-based approach to validate that incoming data conforms to specific types and constraints. It employs a two-way transformation pipeline consisting of separate load and dump phases to handle deserialization and serialization. The framework supports class-based schema definitions with declarative field validation and recursive schema nesting for

Leo is a zero-knowledge proof programming language and a formally verified language designed to prove the mathematical correctness of application logic and cryptographic circuits. It serves as a private application framework and a ZK-circuit compiler that transforms high-level source code into the low-level constraints required to generate and verify zero-knowledge proofs. The project provides a toolset for zero-knowledge application development and ZK circuit engineering, enabling the creation of private smart contract logic. It allows developers to write high-level code that compiles into c

Yup is a JavaScript schema validation library used to define data shapes and validate runtime values. It functions as an object schema validator and a data coercion engine, allowing developers to transform raw input values into desired types before performing validation checks. The library is distinguished by its support for dynamic schema validation, where rules can be adjusted at runtime based on sibling field values or external context. It also enables recursive data structuring for polymorphic fields and provides a system for extracting static TypeScript interfaces from runtime schema def

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

SQLModel is a type-safe object-relational mapping library for Python that integrates database schema definitions with data validation logic. By combining these two roles into a single class, it allows developers to manage relational data structures and enforce data integrity for web APIs simultaneously. The framework is built to support asynchronous database operations, enabling high-performance applications to execute queries and transactions without blocking the main execution thread. The library distinguishes itself by leveraging Python type hints to provide IDE autocompletion and compile-

Inject is a dependency injection library for Go that manages object lifecycles and wires application components by automating the provision of dependencies. It functions as a reflection-based container that maps specific values to their corresponding types, enabling the automatic retrieval and injection of objects into application logic. The library distinguishes itself through its ability to perform automatic function invocation, where it inspects function signatures at runtime to resolve and provide required arguments from a central registry. It also supports struct field injection, which p

koanf is a configuration management library for Go designed to load, merge, and unmarshal application settings from multiple sources into structured objects. It functions as a multi-source config loader that aggregates data from environment variables, files, and remote providers into a single unified map. The system utilizes a pluggable architecture for parsing and data abstraction, allowing it to transform bytes from formats such as JSON, YAML, and TOML into nested maps. It supports dynamic configuration watching to monitor external sources and trigger automatic reloads when settings change.

This project is a comprehensive framework for engineering financial data pipelines, designed to automate the collection, cleaning, and synchronization of large-scale market datasets. It functions as a quantitative trading data engine, providing the infrastructure necessary to manage historical and real-time asset pricing information for research and machine learning workflows. The system distinguishes itself through a configuration-driven approach to orchestration, allowing users to manage complex data acquisition tasks across multiple financial providers. It features resilient middleware tha

dbt-core is a command-line framework for transforming data within a warehouse using modular SQL and version control. It functions as a data transformation engine that enables users to define data structures and business logic through declarative configuration files, which the system then compiles into executable code. By managing complex data dependencies through a directed acyclic graph, it ensures that transformation tasks execute in the correct order while maintaining a manifest-driven state to track lineage and execution history. The project distinguishes itself through an adapter-based d