Feature Matrix

* Effect Schema's bundle size depends on how much of the Effect ecosystem is already in your project. If you are already using Effect, the marginal cost is minimal.

Library Overviews

Zod

The most popular TypeScript schema library. Zod offers an intuitive fluent API, excellent type inference, and the largest ecosystem of integrations (tRPC, React Hook Form, Next.js, Drizzle ORM, and more). Zod v4 brought significant performance improvements and API refinements. Choose Zod when ecosystem compatibility and community support are priorities.

Yup

One of the original JavaScript validation libraries, Yup is still widely used in Formik projects. It has a similar fluent API to Zod but was designed before TypeScript-first became the norm. TypeScript support has improved over time but type inference is not as tight as Zod or Valibot. Choose Yup if you are using Formik and need its native integration.

Joi

The most feature-rich validation library, originally from the Hapi ecosystem. Joi excels at complex validation scenarios with a vast API surface. However, its large bundle size (~35kB) and limited TypeScript inference make it less suited for modern TypeScript applications. Choose Joi for server-side validation where bundle size does not matter and you need advanced validation features.

io-ts

A functional programming approach to runtime validation using TypeScript codecs. Built on fp-ts, io-ts provides excellent type inference but has a steep learning curve for developers unfamiliar with functional programming patterns. io-ts is now deprecated — the maintainer recommends migrating to Effect Schema. Choose io-ts only if your project already uses it; otherwise, consider Zod or Effect Schema.

Valibot

The bundle-size champion at approximately 1kB gzipped thanks to full tree-shaking. Valibot uses a pipe-based API that only includes the validators you actually use. It offers TypeScript inference on par with Zod and supports Standard Schema 1.0. Choose Valibot when bundle size is a primary concern (mobile apps, edge functions, client-heavy applications).

ArkType

A unique approach using string-based syntax that reads like TypeScript type annotations (type({ name: "string", age: "number > 0" })). ArkType provides excellent type inference and claims the fastest validation performance. The trade-off is a larger bundle size and a syntax that may feel unfamiliar. Choose ArkType if you value concise schema definitions and performance.

Superstruct

A lightweight library (~2kB) using bare function composition instead of method chaining. Superstruct is tree-shakeable and has a clean, minimal API. It has good TypeScript support but a smaller ecosystem than Zod. Choose Superstruct for projects that need a small footprint with a straightforward API.

Effect Schema

Part of the Effect ecosystem for building type-safe, composable TypeScript applications. Effect Schema provides rich validation with transformations, encoding/decoding, and integration with the broader Effect toolkit. Choose Effect Schema if your project already uses Effect or you need advanced data transformation pipelines.

Standard Schema 1.0

Standard Schema is a specification that defines a common interface for TypeScript schema validation libraries. It enables frameworks like tRPC v11 to accept any conforming schema library without library-specific adapters.

Libraries implementing Standard Schema: Zod (v3.23+), Valibot (v1+), ArkType (v2+), and Effect Schema. This means you can use any of these libraries interchangeably in Standard Schema-compatible frameworks.

Choosing the Right Library

Priority	Recommended Library	Why
Ecosystem & community	Zod	Largest ecosystem, most framework integrations, most tutorials and resources
Bundle size	Valibot	~1kB with tree-shaking; ideal for client-side and edge deployments
Functional programming	Effect Schema	Native Effect integration, composable pipelines, encoding/decoding
Concise syntax	ArkType	String-based definitions read like TypeScript types, fast validation
Minimal footprint	Superstruct	~2kB, clean API, tree-shakeable, no method chaining
Formik integration	Yup	Native Formik support without adapters
Server-side validation	Joi	Most feature-rich validation API, battle-tested in production

Migrate Between Any Library

SchemaShift automates migration between all eight libraries. Analyze your current schema usage, preview the migration, and convert with a single command:

# Analyze your project
schemashift analyze ./src

# Preview migration
schemashift migrate ./src -f yup -t zod --dry-run

# Compare libraries side-by-side
schemashift compare ./src -f zod -t valibot

# Run migration
schemashift migrate ./src -f yup -t zod

All Migration Guides

Get Started

Use SchemaShift to automate migration between any of these libraries. Analyze your project, preview changes, and migrate with confidence.

npm install -g schemashift-cli

Basic migrations are free. Need advanced features? View pricing.