Wix CLI Backend API

Wix Backend API Builder

Creates HTTP endpoints for Wix CLI applications — server-side routes that handle HTTP requests, process data, and return responses. HTTP endpoints are powered by Astro endpoints and are automatically discovered from the file system.

Key facts:

• Files live in src/pages/api/ with .ts extension
• Cannot be added via npm run generate — create files directly
• Don't appear on the Extensions page in the app dashboard
• No extension registration needed (auto-discovered)
• Replace the legacy "HTTP functions" from the previous Wix CLI for Apps

Use Cases

Use HTTP endpoints when you need to:

• Build REST APIs with multiple HTTP methods
• Integrate with external APIs or services
• Handle complex form submissions or file uploads
• Serve dynamic content (images, RSS feeds, personalized data)
• Access runtime data or server-side databases

File Structure and Naming

Basic Endpoint

File path determines the endpoint URL:

src/pages/api/<your-endpoint-name>.ts

Dynamic Routes

Use square brackets for dynamic parameters:

src/pages/api/users/[id].ts → /api/users/:id
src/pages/api/posts/[slug].ts → /api/posts/:slug
src/pages/api/users/[userId]/posts/[postId].ts → /api/users/:userId/posts/:postId

HTTP Methods

Export named functions for each HTTP method. Type with APIRoute from astro. Each handler receives a request object and returns a Response:

import type { APIRoute } from "astro";

export const GET: APIRoute = async ({ request }) => {
  console.log("Log from GET."); // This message logs to your CLI.
  return new Response("Response from GET."); // This response is visible in the browser console
};

export const POST: APIRoute = async ({ request }) => {
  const data = await request.json();
  console.log("Log POST with body: ", data); // This message logs to your CLI.
  return new Response(JSON.stringify(data)); // This response is visible in the browser console.
};

Request Handling

Path Parameters

export const GET: APIRoute = async ({ params }) => {
  const { id } = params; // From /api/users/[id]

  if (!id) {
    return new Response(JSON.stringify({ error: "ID required" }), {
      status: 400,
      statusText: "Bad Request",
      headers: { "Content-Type": "application/json" },
    });
  }

  // Use id to fetch data
};

Query Parameters

Use new URL(request.url).searchParams:

export const GET: APIRoute = async ({ request }) => {
  const url = new URL(request.url);
  const search = url.searchParams.get("search");
  const limit = parseInt(url.searchParams.get("limit") || "10", 10);
  const offset = parseInt(url.searchParams.get("offset") || "0", 10);

  // Use query parameters
};

Request Body

Parse JSON body from POST/PUT/PATCH requests:

export const POST: APIRoute = async ({ request }) => {
  try {
    const body = await request.json();
    const { title, content } = body;

    if (!title || !content) {
      return new Response(
        JSON.stringify({ error: "Title and content required" }),
        {
          status: 400,
          statusText: "Bad Request",
          headers: { "Content-Type": "application/json" },
        }
      );
    }

    // Process data
  } catch {
    return new Response(JSON.stringify({ error: "Invalid JSON" }), {
      status: 400,
      statusText: "Bad Request",
      headers: { "Content-Type": "application/json" },
    });
  }
};

Headers

const authHeader = request.headers.get("Authorization");
const contentType = request.headers.get("Content-Type");

Response Patterns

Always return a Response object with proper status codes and headers:

// 200 OK
return new Response(JSON.stringify({ data: result }), {
  status: 200,
  headers: { "Content-Type": "application/json" },
});

// 201 Created
return new Response(JSON.stringify({ id: newId, ...data }), {
  status: 201,
  headers: { "Content-Type": "application/json" },
});

// 204 No Content (for DELETE)
return new Response(null, { status: 204 });

// 400 Bad Request
return new Response(JSON.stringify({ error: "Invalid input" }), {
  status: 400,
  statusText: "Bad Request",
  headers: { "Content-Type": "application/json" },
});

// 404 Not Found
return new Response(JSON.stringify({ error: "Not found" }), {
  status: 404,
  statusText: "Not Found",
  headers: { "Content-Type": "application/json" },
});

// 500 Internal Server Error
return new Response(JSON.stringify({ error: "Internal server error" }), {
  status: 500,
  statusText: "Internal Server Error",
  headers: { "Content-Type": "application/json" },
});

Frontend Integration

Call HTTP endpoints from frontend components using Wix's built-in HTTP client (httpClient.fetchWithAuth()):

import { httpClient } from "@wix/essentials";

// GET request
const baseApiUrl = new URL(import.meta.url).origin;
const res = await httpClient.fetchWithAuth(
  `${baseApiUrl}/api/<your-endpoint-name>`,
);
const data = await res.text();

// POST request
const res = await httpClient.fetchWithAuth(
  `${baseApiUrl}/api/<your-endpoint-name>`,
  {
    method: "POST",
    body: JSON.stringify({ message: "Hello from frontend" }),
  },
);
const data = await res.json();

Build, Deploy, and Delete

To take HTTP endpoints to production, build and release your project:

1. Build the project assets using the build command.
2. Optionally create preview URLs using the preview command to share with team members for testing.
3. Release your project using the release command.

Once released, endpoints are accessible at production URLs and handle live traffic.

To delete an HTTP endpoint, remove the file under src/pages/api/ and release again.

Output Structure

src/pages/api/
├── users.ts              # /api/users endpoint
├── users/
│   └── [id].ts           # /api/users/:id endpoint
└── posts.ts              # /api/posts endpoint

Code Quality Requirements

• Strict TypeScript (no any, explicit return types)
• Type all handlers with APIRoute from astro
• Always return Response objects with JSON.stringify() for JSON
• Proper HTTP status codes (200, 201, 204, 400, 404, 500)
• Include Content-Type: application/json header on JSON responses
• Include statusText in error responses
• Handle errors with try/catch blocks
• Validate input parameters and request bodies
• Use async/await for asynchronous operations
• No @ts-ignore comments

Verification

After implementation, use wix-cli-app-validation to validate TypeScript compilation, build, preview, and runtime behavior.