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Getting started

Requirements
  • Next.js >= 14
  • React >= 18.2.0
  • TypeScript >= 5
  • A validation library supported by Standard Schema

next-safe-action provides a typesafe Server Actions implementation for Next.js App Router applications.

Installation​

npm i next-safe-action

Usage​

1. Instantiate a new client​

You can create a new client with the following code:

src/lib/safe-action.ts
import { createSafeActionClient } from "next-safe-action";

export const actionClient = createSafeActionClient();

This is a basic client, without any options or middleware functions. If you want to explore the full set of options, check out the create the client section.

2. Define a new action​

This is how a safe action is created. Providing a validation input schema to the function via inputSchema(), we're sure that data that comes in is type safe and validated. The action() method lets you define what happens on the server when the action is called from client, via an async function that receives the parsed input and context as arguments. In short, this is your server code. **It never runs on the client.

In this documentation, we'll use the Zod library to define our validation logic, but feel free to use any other library that implements the Standard Schema specification.

src/app/login-action.ts
"use server"; // don't forget to add this!

import { z } from "zod";
import { returnValidationErrors } from "next-safe-action";
import { actionClient } from "@/lib/safe-action";

// This schema is used to validate input from client.
const inputSchema = z.object({
  username: z.string().min(3).max(10),
  password: z.string().min(8).max(100),
});

export const loginUser = actionClient
  .inputSchema(inputSchema)
  .action(async ({ parsedInput: { username, password } }) => {
    if (username === "johndoe" && password === "123456") {
      return {
        success: "Successfully logged in",
      };
    }

    return returnValidationErrors(inputSchema, { _errors: ["Incorrect credentials"] });
  });

action returns a function that can be called from the client.

3. Import and execute the action​

In this example, we're directly calling the Server Action from a Client Component:

src/app/login.tsx
"use client"; // this is a Client Component

import { loginUser } from "./login-action";

export default function Login() {
  return (
    <button
      onClick={async () => {
        // Typesafe action called from client.
        const res = await loginUser({
          username: "johndoe",
          password: "123456",
        });

        // Result keys.
        const {
          data,
          validationErrors,
          serverError,
        } = res;
      }}>
      Log in
    </button>
  );
}

You also can execute Server Actions with hooks, which are a more powerful way to handle mutations. For more information about these, check out the useAction and useOptimisticAction hooks sections.