30 open-source projects similar to pydantic/pydantic, ranked by shared indexed features. Tags may describe platforms or build tools rather than the same primary purpose. Check each project’s use case, license, and deployment requirements before treating it as a replacement.
Zod is a TypeScript-first schema declaration and validation library designed to ensure end-to-end data integrity. It functions as a runtime type guard, allowing developers to define complex data structures through a declarative, chainable syntax. By using these schema definitions, the library automatically derives static TypeScript types, eliminating the need for manual type duplication and ensuring that runtime data matches expected application contracts. The library distinguishes itself through functional schema composition, which enables the creation of hierarchical structures by nesting a
Superstruct is a JavaScript and TypeScript data validation library used to verify that data structures match defined shapes and types. It functions as a composable schema builder and a TypeScript schema validator, ensuring that runtime data checks remain synchronized with static type definitions. The library features a data coercion engine that transforms input values or injects default values before the validation process is executed. It enables the creation of complex validation rules by nesting, merging, or omitting properties from existing structures. Its capabilities cover the validatio
Lightweight, extensible data validation library for Python
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
This project serves as a comprehensive resource hub and curated directory for the FastAPI web framework ecosystem. It provides developers with a centralized collection of community-vetted libraries, tools, and best practices designed to support the development, testing, and deployment of scalable web services using modern Python. The repository distinguishes itself by aggregating resources that address the full lifecycle of high-performance API development. It covers essential capabilities including project scaffolding, database integration, and the implementation of real-time communication p
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
Symfony is a full-stack web framework designed for building scalable and maintainable server-side applications. It provides a comprehensive collection of decoupled components that form a foundational architecture, centered on a robust dependency injection container and a configuration-driven routing engine. By organizing code into modular services, the framework ensures that application components remain testable and loosely coupled throughout the development lifecycle. The framework distinguishes itself through an event-driven kernel architecture that allows developers to intercept and modif
Pydantic is a data validation library and parsing framework for Python. It functions as a type-based schema validator that uses standard Python type annotations to ensure input data conforms to predefined structural schemas. The project provides capabilities for parsing raw data into typed objects through automatic type conversion and validation. This includes the serialization of data and the validation of data structures to enforce correctness. The framework covers several application areas, including the verification of API requests and the management of application configurations. It all
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
Library for exploring and validating machine learning data
Algorithms for outlier, adversarial and drift detection
This project is a JSON Schema validation library and framework used to verify that data instances conform to declarative definitions. It functions as a validation engine that enforces structural constraints and data types, while also serving as a meta-validator to ensure schema definitions themselves are syntactically correct against official meta-schemas. The library is designed for extensibility, allowing users to define custom validation logic by mapping schema keywords to specialized callable functions. It includes a registry-based reference resolver for managing internal and external URI
A JSONSchema validator that uses code generation to be extremely fast
Pandera is a data pipeline validation framework and statistical type validation tool. It functions as a library for defining and enforcing schemas on datasets to ensure data quality and consistency, specifically providing validation capabilities for Pandas dataframes. The project includes a schema inference tool that automates setup by analyzing existing dataset samples to generate validation schemas. It also serves as a synthetic data generator, creating artificial datasets based on predefined schemas to verify data-producing functions. The framework covers data engineering quality assuranc
CONTRIBUTIONS ONLY: Voluptuous, despite the name, is a Python data validation library.
:whitecheckmark: Easy property validation for JavaScript, Node and Express.
Ajv is a high-performance data validation framework that compiles JSON schemas into optimized, standalone JavaScript functions. By transforming declarative schema definitions into executable code, it eliminates runtime interpretation overhead and provides a secure, efficient way to enforce data integrity across both browser and server environments. The library distinguishes itself through its focus on performance and type safety. It employs advanced compilation techniques, including abstract syntax tree optimization and function caching, to ensure rapid validation. Beyond standard checks, it
Strawberry is a type-safe GraphQL library for Python that enables the design of schemas using Python type annotations and dataclasses. It functions as an asynchronous GraphQL server and execution engine, providing a bridge to expose schemas across ASGI-compliant web frameworks such as FastAPI, Django, Flask, and Litestar. The project implements GraphQL Federation, allowing for the creation of distributed schemas and entities that merge into a unified supergraph across multiple services. It also includes a dedicated toolkit for the Relay specification, supporting global object identification a
Litestar is a high-performance Python ASGI web framework designed for building asynchronous APIs and web services. It functions as a type-safe toolkit that leverages Python type hints to provide automatic request validation and response serialization, while natively generating interactive API documentation based on the OpenAPI specification. The framework is distinguished by its integrated dependency injection system, which manages shared resources and resolves complex nested service chains directly within request handlers. It further organizes API development through class-based controllers
swagger-php is an OpenAPI specification generator and PHP API documentation library. It scans PHP source code attributes and annotations to produce standardized specification files and interactive API references. The tool functions as a schema inference engine that derives data types and schemas from native PHP type hints and generic blocks. It uses reflection-based static analysis to extract metadata without executing application logic and supports recursive schema inheritance to merge definitions from parent classes and interfaces. The project includes a command-line utility for exporting
FastAPI is a high-performance Python web framework designed for building REST APIs. It operates as an ASGI web framework, providing a system to create structured HTTP endpoints that automatically serialize data and validate request parameters. The framework utilizes Python type hints to drive data validation and serialization, automatically generating machine-readable OpenAPI and JSON Schema specifications. This process enables the automatic creation of interactive, browser-based API documentation where endpoints can be tested directly. The project includes a dependency injection system for
Django Ninja is a high-performance framework for building type-safe REST APIs using Django. It functions as an OpenAPI API framework and a type-safe wrapper that utilizes Python type hints to handle request validation and response serialization. The project distinguishes itself by integrating Pydantic-based data modeling to convert JSON inputs into strongly typed Python objects. It automatically generates OpenAPI schemas and interactive documentation pages directly from defined endpoint signatures. The framework supports asynchronous request processing to handle concurrent tasks. It employs
Pothos is a code-first GraphQL schema builder and framework designed for type-safe development. It allows developers to construct schemas using typed definitions in TypeScript, eliminating the need for external code generation steps. The framework distinguishes itself through a dedicated data mapper that connects GraphQL types to relational databases and ORMs, such as Prisma, while optimizing query resolution. It provides a full implementation of the Relay specification, including global object identification and cursor-based pagination. The project covers several core capability areas, incl
t3-env is a type-safe environment manager and schema validator for TypeScript. It maps environment variables to static types to provide autocompletion and prevents configuration errors through a system that verifies required variables are present and correctly formatted before an application starts. The project enforces strict variable scope to isolate server-side secrets from the client browser, preventing sensitive data from leaking into client-side bundles. It also provides configuration presets tailored to the naming conventions of specific hosting and deployment platforms. The library i
This project is a customizable browser text editor and a schema-driven document framework designed for building React-based WYSIWYG content editors. It replaces standard text areas with a system that represents content as a structured data tree rather than flat HTML, allowing for precise manipulation and validation of documents. The framework serves as an extensible content management interface and a TypeScript UI component library. It enables the development of specialized authoring tools through a plugin system and the use of strongly typed building blocks to ensure consistency across docum
Backbone.validation is a JavaScript library designed to enforce data integrity within Backbone.js models. It provides a framework for defining declarative validation schemas that intercept attribute changes, ensuring that data meets specified business requirements before it is committed to the model. The library distinguishes itself by tightly coupling model-level validation with user interface components. It features an event-driven binding system that monitors model states and automatically triggers interface updates, providing real-time feedback as users interact with forms. This approach
Elysia is a high-performance TypeScript web framework designed for building type-safe backend services. It provides a modular, plugin-based architecture that allows developers to compose server logic, middleware, and validation schemas into scalable application instances. By leveraging native web standards, the framework ensures portability across diverse JavaScript runtimes, including Node.js, Deno, and various edge computing environments. The framework distinguishes itself through its focus on end-to-end type safety, automatically synchronizing request and response definitions between the s
FastMCP is a Python framework designed for building servers that expose functions, resources, and prompts to AI models using the Model Context Protocol. It simplifies the development process by automatically deriving tool metadata, input schemas, and documentation directly from Python function signatures and type hints. The framework provides a unified container for managing these components, allowing developers to build modular applications that integrate seamlessly with AI assistants. The project distinguishes itself through its support for interactive, server-defined user interface compone
Aria2 is a multi-protocol command-line download manager designed to maximize bandwidth utilization by retrieving files from multiple sources and protocols simultaneously. It functions as an asynchronous, event-driven engine that handles complex download lifecycles, including peer-to-peer transfers via BitTorrent, while ensuring data integrity through continuous chunk-based verification. The utility distinguishes itself through its ability to act as a background process that can be controlled programmatically via a remote procedure call interface. This allows external applications to manage, m