30 open-source projects similar to epoberezkin/ajv, 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.
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
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 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
This project is a Python implementation of the JSON Schema specification, providing a library for verifying that data instances conform to defined schemas. It serves as a data validation framework capable of validating both the data itself and the schemas against official meta-schemas to ensure structural correctness. The library features a schema reference resolver that maps URIs to definitions, enabling the resolution of internal and remote references for modular schema management. It is designed for extensibility, allowing for the definition of custom keywords, custom type-checking logic,
AWS Powertools for Python is a utility framework designed for building production-ready Python functions on AWS Lambda. It provides a comprehensive suite of tools for observability, event parsing, routing, and idempotency management to streamline the development of serverless applications. The project distinguishes itself through specialized capabilities for event-driven architectures and AI agent orchestration. It enables the implementation of AI agents by exposing functions as tools via OpenAPI schemas and managing conversation states. Additionally, it features an idempotency library that p
This project is a Java library designed to validate JSON documents against defined schema specifications. It functions as a standards-compliant engine that ensures data integrity by checking structural compliance and enforcing business rules within Java applications. The library distinguishes itself through its flexible validation strategies, allowing developers to inject custom logic and pattern-matching engines to handle specialized data formats. It supports configurable execution modes, enabling users to either halt validation immediately upon the first error or collect all violations for
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
Generate Java types from JSON or JSON Schema and annotate those types for data-binding with Jackson, Gson, etc
The YAML Language Server is a backend service that provides intelligent editing support for YAML files by implementing the Language Server Protocol. It functions as a validation and analysis engine, enabling code editors to offer real-time diagnostics, structural feedback, and automated assistance for configuration-heavy development workflows. The project distinguishes itself through its schema-driven approach to data integrity, utilizing a JSON Schema validation engine to verify document structure against formal definitions. It supports complex configuration management by allowing developers
Kinto is a cloud state backend designed for storing and synchronizing JSON data across multiple devices. It provides a centralized service for managing schema-less JSON records organized into buckets and collections, ensuring a consistent state through a REST API. The system supports collaborative data sharing by granting read and write access to specific documents or collections via user groups and permissions. It enables document synchronization using change feed tracking and deletion markers to update clients with the latest state. Capabilities include fine-grained access control, JSON sc
TypeBox is a JSON schema generator and TypeScript data validator. It functions as a type builder that creates compliant JSON schema definitions while providing a mechanism for synchronizing runtime validation logic with compile-time types. The project allows for the automatic derivation of static TypeScript interfaces from schema definitions to eliminate redundant type declarations. It converts complex type constructs into schema fragments and resolves static types to maintain consistency between data shapes and code. The system covers runtime type checking and data validation through the us
This library is a Ruby-based validation engine designed to verify JSON data structures against official schema specifications. It ensures data integrity by confirming that objects, strings, and files conform to defined structural constraints, while also validating the integrity of the schema definitions themselves against official metaschema standards. The project distinguishes itself through a highly modular architecture that allows for deep customization. Users can register custom validation rules and format handlers to enforce project-specific business logic that extends beyond standard sp
Eve is a REST API framework that maps database collections to web resources through declarative configuration files. It functions as a database-to-API mapper, automatically exposing data as RESTful endpoints with built-in support for CRUD operations and schema-based request validation. The project distinguishes itself through a HATEOAS API engine that generates hypermedia links and resource schemas for dynamic client discovery. It also includes an automated Swagger documentation generator that produces interactive specifications for client SDK generation and testing. The framework provides a
CUE is a constraint-based configuration language designed for data validation, schema definition, and code generation. At its core, it unifies types and values into a single concept, enabling compile-time validation that catches structural and value errors before runtime. The language treats data and constraints as the same thing, allowing a single definition to serve as both a schema and concrete configuration data. CUE distinguishes itself through its constraint-based unification engine, which combines multiple configuration sources into a single coherent result by merging their constraints
json_repair is a Python library that automatically fixes common JSON syntax errors, such as trailing commas, missing quotes, unclosed brackets, and stray text, producing valid JSON output. It can also complete broken structures by closing unclosed arrays and objects, and fill missing values with sensible defaults like empty strings or null. The library distinguishes itself by handling JSON from large language model outputs, stripping markdown fences, comments, and surrounding prose before parsing. It supports schema-guided repairs, using a JSON Schema to fill missing values, coerce data types
Valibot is a modular, type-safe schema library for validating and parsing structural data in TypeScript environments.
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
The inspector is a diagnostic and validation tool for the Model Context Protocol. It provides an interactive interface and a transport proxy to discover, inspect, and execute the tools, prompts, and resources provided by an MCP server. The project serves as a debugger and compliance tester to verify that server implementations adhere to the protocol specification and JSON-RPC standards. It allows for real-time monitoring of message exchanges and logs between clients and servers across various transport layers, such as standard input/output and Server-Sent Events. The tool covers a broad rang
fast-json-stringify is a high-performance JSON serialization library that uses JSON Schema to compile optimized functions for converting JavaScript objects into strings. It serves as a schema-based JSON serializer that generates specialized serialization logic to outperform standard stringification methods. The project provides capabilities to export standalone serialization code to files for direct execution and supports schema reference resolution to eliminate logic duplication. It allows for the deactivation of character escaping for trusted data to reduce overhead and includes specific op
json-joy is a comprehensive library for building real-time collaborative applications and distributed systems. It provides a robust framework for managing shared JSON-like data structures that automatically merge concurrent edits from multiple users, ensuring consistent state across all replicas without requiring a central coordination server. The project distinguishes itself through a high-performance approach to data handling, utilizing conflict-free replicated data types and logical clock-based synchronization to maintain data integrity. It includes a specialized engine for navigating and
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
Kùzu is an embedded property graph database engine designed for high-performance analytical queries and local data management. It operates as a library within the host application process, utilizing a columnar-based storage architecture and just-in-time query compilation to execute complex graph traversals and pattern matching efficiently. By mapping database files directly into system memory, it ensures data durability and high-speed access while maintaining ACID-compliant transactional integrity. The engine distinguishes itself by integrating vector similarity search and full-text search di
Rushstack is a comprehensive toolset for managing large-scale TypeScript monorepos, providing a framework for build pipeline automation, dependency coordination, and static analysis. It functions as an incremental build orchestrator and management system designed to maintain consistency and performance across multiple packages in a shared workspace. The system distinguishes itself through an execution model based on directed acyclic graphs and content-hash-based incrementalism, which ensures only affected projects are rebuilt. It further optimizes development workflows via remote build artifa
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 library provides a comprehensive system for defining data schemas and enforcing structural integrity within JavaScript applications. It enables developers to construct declarative rules for complex, nested objects, ensuring that data conforms to expected types and constraints before it is processed or stored. By integrating directly with the Meteor framework, it serves as a central tool for maintaining consistent data structures across collections and remote procedure calls. The project distinguishes itself through its deep integration with reactive data systems, allowing validation stat
Vee-validate is a form validation library and state management tool for Vue applications. It enables the validation of user inputs through declarative rules and tracks form metadata, including submission status and dirty states. The library functions as a wrapper for integrating external schema validation libraries to enforce consistent data shapes. It also serves as an internationalized framework for displaying translated error messages and localized feedback. The project covers broad capability areas including form state management, the handling of complex nested data structures, and the s
async-validator is a JavaScript schema validation library and asynchronous data validation engine. It verifies complex object structures and nested arrays by applying recursive rules and non-blocking, promise-based execution to ensure data integrity. The library functions as both an object constraint validator and a data transformation pipeline. It allows for the sanitization, coercion, and formatting of input values through a sequence of functions that run before and after the primary validation process. The engine covers a range of capabilities including recursive nested validation, the en
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
This library is a Java-based tool for enforcing data structure constraints and verifying technical formats against defined schema specifications. It functions as a processing utility that parses complex data structures while managing external schema references and circular dependencies. The engine distinguishes itself through an immutable processor design that enables thread-safe, concurrent validation without requiring external synchronization. It employs arbitrary-precision arithmetic to evaluate numeric constraints, preventing common floating-point rounding errors, and utilizes character-l
Joi is a JavaScript data validation library used to define schemas that ensure the structure and data types of objects remain consistent. It functions as a schema-based validator and object schema definition tool, preventing invalid information from entering an application by checking data against predefined constraints and rules. The library employs a chainable fluent interface and a constraint-based validation engine to build complex validation pipelines. It utilizes recursive tree traversal to validate nested data structures and a type-coercion pipeline to transform input values into the t