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Quick Start/
Connect Frontend To Backend

Connect Frontend To Backend

Your stack:

Goal

Connect a Next.js app to backend logic with Graftcode - no REST clients, no DTOs, no handwritten integration code.

What You'll See

  • Install a typed Graft from a live backend service instead of writing REST client code.
  • Configure the generated client to point at a sample backend server.
  • Call a backend method directly from a Next.js client component as if it were local code.
  • Use IDE autocompletion on backend methods and types - powered by the installed Graft package.

Prerequisites

Step 1. Start with a Next.js app

This gives you a working Next.js app where you can add your first Graft.

git clone https://github.com/grft-dev/nextjs-hello-world
cd nextjs-hello-world
npm install

Step 2. Open the backend in Graftcode Vision

Before you install anything, compare the two views of the same backend:

  • Swagger shows routes, verbs, and payloads.
  • Graftcode Vision shows public classes and methods and gives you the package manager command to install them.

This is the key Graftcode shift: instead of reading an API spec and building a client, you install the service as a dependency and call methods directly.

Step 3. Install the Graft

Open Graftcode Vision, pick npm, and copy the generated install command.

npm install --registry https://grft.dev/11ee1b4f-1a87-4b7d-9112-1ada3ad69b9e__free @graft/nuget-energypriceservice@1.3.0

The command above is a snapshot for this guide. The registry UUID and package version can change - always prefer the install command currently shown in Graftcode Vision.

Step 4. Configure the generated client

Open app/page.js and connect the generated client to the service host. The exact configuration snippet for your language is available in Graftcode Vision under the Configuration installation tab:

"use client";

import { useEffect, useState } from "react";
import { BillingLogic, GraftConfig } from "@graft/nuget-energypriceservice";

GraftConfig.host = "wss://g-d-ca-polc-demo-ecbe-01.nicedesert-fa74799d.polandcentral.azurecontainerapps.io/ws";

@graft/nuget-energypriceservice is the Graft you installed - it exposes the backend's public classes and methods as normal JavaScript imports. Setting GraftConfig.host tells the client where the backend is running.

Next.js pre-renders pages on the server. The Graft client talks to the backend over a WebSocket, so this page must be a Client Component ("use client"). Keep the method call in the browser, in useEffect, not during server render.

The Graft package bootstraps Node with node:module and node:url. Next.js webpack does not bundle those schemes for the browser, so npm run dev fails while compiling app/page.js unless next.config.mjs externalizes the package on the server and strips the node: prefix in the client build. This starter already includes that file:

/** @type {import('next').NextConfig} */
const nextConfig = {
  serverExternalPackages: ["@graft/nuget-energypriceservice", "hypertube-nodejs-sdk"],
  webpack: (config, { isServer, webpack }) => {
    if (isServer) {
      return config;
    }

    config.plugins.push(
      new webpack.NormalModuleReplacementPlugin(/^node:/, (resource) => {
        resource.request = resource.request.replace(/^node:/, "");
      })
    );
    config.resolve.fallback = {
      ...config.resolve.fallback,
      module: false,
      url: false,
      fs: false,
      path: false,
    };
    return config;
  },
};

export default nextConfig;

Keep this config if you replace next.config.mjs. The dev server may still print a warning that the Graft package uses top-level await. The page still renders the bill.

Step 5. Call a backend method

BillingLogic is a class from the backend, and calculateMonthlyBill(...) is one of its public methods - the same ones you browsed in Graftcode Vision. The npm Graft uses camelCase method names even when the backend or Vision shows PascalCase from C#. You call it like any other imported function.

"use client";

import { useEffect, useState } from "react";
import { BillingLogic, GraftConfig } from "@graft/nuget-energypriceservice";

GraftConfig.host = "wss://g-d-ca-polc-demo-ecbe-01.nicedesert-fa74799d.polandcentral.azurecontainerapps.io/ws";

export default function Page() {
  const [data, setData] = useState(null);

  useEffect(() => {
    BillingLogic.calculateMonthlyBill(88.4, 1.4, 23).then(setData);
  }, []);

  return <h1>Calculated Energy Monthly Bill is: {data?.toFixed(2)}</h1>;
}

Step 6. Run the app

Start the development server:

npm run dev

In this starter, npm run dev runs Next.js. Open the URL shown in the terminal (typically http://localhost:3000). You should see the calculated energy bill rendered on the page.

If something is not working, expand below to see the full app/page.js source:

Step 7. Explore more methods and keep up with backend changes

Go back to Graftcode Vision to inspect more methods on BillingLogic.

Your IDE can autocomplete available methods and arguments because the service is installed as a typed package, not consumed through handwritten API code. Your AI can now generate frontend code using backend methods as easily as using other npm modules you imported.

When the backend evolves - new methods, changed signatures, updated types - the Graft package version updates just like any other npm package. You see the change in your package.json, update with a single command, and your IDE immediately reflects the new API surface:

npm update @graft/nuget-energypriceservice

No need to regenerate clients, rewrite fetch calls, or re-sync OpenAPI specs. Backend changes flow through the same package manager workflow you already use for every other dependency.

NextExpose Backend