How to validate nested objects with Valibot?

Use the object schema method to define nested properties, composing schemas for each level. For example, nest object or array schemas within parent objects to handle complex structures easily.

Valibot vs Zod: which is better for TypeScript projects?

Valibot excels in modularity and smaller bundle sizes, ideal for performance-sensitive apps, while Zod offers a larger ecosystem and community support. Choose based on bundle size priorities versus integration ease.

Can I use Valibot with React forms?

Yes, Valibot integrates seamlessly with React by providing validation functions for form handlers. It's recommended in the context for building type-safe form validation in React applications.

Does Valibot support asynchronous validation?

Yes, Valibot has built-in support for asynchronous validation pipelines, allowing async operations like API calls or database checks within validation logic, as noted in the Key Features.

How to add custom error messages in Valibot?

Extend validation rules using custom validators or built-in options to define tailored error messages. This flexibility is highlighted in the Key Features for enhancing user feedback.

Is Valibot suitable for server-side validation?

Absolutely, Valibot is well-suited for server-side use cases like API payload validation and configuration parsing, thanks to its zero dependencies and structural validation capabilities.

valibot — TypeScript Schema Library

What is valibot?

Valibot is a TypeScript schema validation library that enables developers to define data schemas, validate structural data at runtime, and automatically infer TypeScript types. It solves the problem of maintaining consistency between runtime data validation and static type checking in TypeScript applications.

Target Audience

TypeScript developers building applications that require robust data validation, including API input validation, form validation, configuration parsing, and data transformation pipelines.

Value Proposition

Developers choose Valibot for its excellent TypeScript integration, modular architecture that minimizes bundle size, and zero-dependency design that simplifies integration and reduces maintenance overhead compared to alternatives.

Overview

The modular and type safe schema library for validating structural data 🤖

Use Cases

Best For

Validating API request/response payloads in TypeScript backends
Building type-safe form validation in React/Vue applications
Parsing and validating configuration files with complex structures
Creating runtime type guards for external data sources
Implementing data transformation pipelines with validation steps
Reducing bundle size in frontend applications through modular imports

Not Ideal For

Projects built entirely in vanilla JavaScript without TypeScript adoption
Simple validation tasks where overhead from a modular library is unnecessary
Teams already deeply integrated with alternatives like Zod or Joi

Pros & Cons

Pros

Modular Architecture

Allows importing only necessary validation functions, significantly reducing bundle size as highlighted in the Key Features for frontend optimization.

TypeScript Integration

Automatically infers static TypeScript types from schemas, ensuring consistency between runtime validation and compile-time type checking without manual definitions.

Zero Dependencies

Self-contained with no external runtime dependencies, simplifying integration and reducing maintenance overhead compared to libraries with dependency chains.

Custom Validation Support

Enables extending functionality with custom validation rules and error messages, providing flexibility for specific application needs as mentioned in the Key Features.

Cons

TypeScript Reliance

Optimal use requires TypeScript, making it less effective for JavaScript-only projects where its type inference features are underutilized.

Smaller Ecosystem

As a newer library, it has a smaller community and fewer third-party integrations compared to established alternatives like Zod, which may limit ready-made solutions.

Functional Complexity

The composable, functional approach can have a steeper learning curve for developers accustomed to more imperative or object-oriented validation libraries.

Open Source Alternative To

valibot is an open-source alternative to the following products:

J

Joi

Joi is a powerful schema description language and data validator for JavaScript objects, commonly used in Node.js applications for input validation.

Z

Zod

Zod is a TypeScript-first schema declaration and validation library that allows developers to define data schemas and validate data at runtime with type safety.

A

Ajv

Ajv (Another JSON Schema Validator) is a fast JSON schema validator for JavaScript that supports draft-04, draft-06, and draft-07 specifications.

S

Superstruct

Superstruct is a JavaScript library for validating and structuring data, commonly used for runtime type checking and data validation in applications.

Y

Yup

Yup is a JavaScript object schema validator and object parser, often used for form validation in web applications.