Zodios is a comprehensive REST API toolbox designed to provide end-to-end typesafety for modern web applications. Created by ecyrbe, the project aims to simplify the development process by allowing developers to define APIs in a declarative, intuitive syntax while ensuring consistency between frontend and backend implementations. By leveraging Zod for schema definitions and TypeScript for type safety, Zodios enables developers to create robust API clients and servers with minimal boilerplate. The system is highly modular, allowing frontend and backend teams to scale development independently by sharing a common API definition. While optimized for TypeScript, Zodios remains fully functional in pure JavaScript environments.

Zodios functions by providing a unified API definition that serves as a single source of truth for both the client and the server. The core library handles the heavy lifting of validation and type generation, ensuring that request inputs and response structures match predefined Zod schemas. This end-to-end validation eliminates common runtime errors and improves the developer experience through enhanced autocompletion and type inference, whether building standalone clients or integrated servers.

Some of the key features are:

• Shared API Definitions: Utilizes Zod to create declarative API contracts that are shared between frontend and backend modules.
• Typesafe Client: Provides an Axios-based API client with built-in parameter and response validation, alongside TypeScript type generation.
• Typesafe Server: Offers an Express-compatible adapter that ensures incoming network requests are validated against defined schemas.
• Frontend Integration: Includes ready-to-use hooks for React and Solid, based on TanStack Query, for efficient data fetching.
• OpenAPI Support: Includes helpers for generating OpenAPI specifications directly from Zodios API definitions and provides integrations for Swagger UI.
• Plugin System: Features a powerful plugin architecture for extending client capabilities and customizing API interactions.

Operationally, developers start by defining their API structure using Zod schemas. This definition acts as the contract. On the backend, this contract is passed to the Zodios router or application factory to enforce validation on routes implemented with Express. On the frontend, the same definition is consumed by the Zodios client or framework-specific hooks to enable autocompletion and typesafe data access. This approach ensures that any change in the API schema propagates automatically to all parts of the application, maintaining synchronization without manual updates to types.

Some common use cases include:

• Full-Stack Application Development: Building a cohesive NextJS application where the API layer and the frontend components share the same types, reducing cross-layer bugs.
• Microservices Communication: Using the Zodios client in a service-oriented architecture to maintain strict communication contracts between different internal services.
• Rapid API Prototyping: Generating both documentation and a fully typed client simultaneously from a central schema, speeding up the time-to-market for new features.
• API Refactoring: Safely updating API endpoints with immediate compiler feedback across the entire codebase to detect breaking changes before deployment.