Node.js Server Quickstart

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Overview

• Set up a Fastify server with a Fingerprint integration
• Retrieve visitor identification data using the Server API
• Block bots and suspicious devices
• Prevent multiple signups from the same device

Estimated time: < 10 minutes

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Prerequisites

• A completed frontend or mobile Fingerprint implementation (See the quickstarts)
• Node.js (v20 or later) and npm installed
• Your favorite code editor
• Basic knowledge of JavaScript

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1. Get your secret API key

1. Sign in and go to the API keys page in the Fingerprint dashboard.
2. Create a new secret API key.
3. Copy it somewhere safe so you can use it to retrieve full visitor identification data from the Server API.

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2. Set up your project

1. Create a new Node project and install Fastify and the Fingerprint Node Server SDK:

mkdir fingerprint-node-quickstart && cd fingerprint-node-quickstart
npm init -y
npm install fastify @fingerprintjs/fingerprintjs-pro-server-api

2. Enable ES modules by updating the type in your package.json to be module:

{
  "type": "module"
}

3. Create a new file called server.js and add a basic Fastify server setup:

import Fastify from "fastify";

const app = Fastify();

app.post("/api/create-account", async (request, reply) => {
  // We'll add Fingerprint logic here
  return reply.send({ status: "Account created!" });
});

app.listen({ port: 3000 }, (err) => {
  if (err) throw err;
  console.log("Server running on http://localhost:3000");
});

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3. Initialize Fingerprint and retrieve visitor data

1. At the top of your server.js file, import and initialize the SDK with your secret API key:

import { FingerprintJsServerApiClient, Region } from "@fingerprintjs/fingerprintjs-pro-server-api";

const client = new FingerprintJsServerApiClient({
  apiKey: "SECRET_API_KEY", // Replace with your actual secret key
  region: Region.Global, // Change to your Fingerprint workspace region
});

2. In your /api/create-account route, retrieve the requestId you are sending from the frontend and fetch the full visitor identification details with getEvent():

app.post("/api/create-account", async (request, reply) => {
  const { requestId, username, password } = request.body;
  const event = await client.getEvent(requestId);

  //...

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4. Block bots and suspicious devices

1. Continuing in your /api/create-account route, check the bot signal returned in the event object:

const botDetected = event.products.botd.data.bot.result !== "notDetected";

if (botDetected) {
  return reply.code(403).send({ error: "Failed to create account." });
}

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5. Prevent multiple signups from the same device

1. Install the SQLite package:

npm install sqlite3

2. At the top of your server.js file, import and initialize the database:

import sqlite3 from "sqlite3";

const db = new sqlite3.Database("database.db");

db.run(`
  CREATE TABLE IF NOT EXISTS accounts (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    username TEXT,
    password TEXT,
    visitorId TEXT
  )
`);

3. In your /api/create-account route handler, after getting the event, extract the visitorId:

const visitorId = event.products.identification.data.visitorId;

4. Check if this device has already created an account; if yes, block the account creation:

// Check if the visitorId already exists in the database
const existingRow = await new Promise((resolve, reject) => {
  db.get("SELECT COUNT(*) as count FROM accounts WHERE visitorId = ?", [visitorId], (err, row) => {
    if (err) reject(err);
    resolve(row);
  });
});

if (existingRow.count > 0) {
  return reply.code(429).send({ error: "Failed to create account." });
}

// Otherwise, insert the new account
await new Promise((resolve, reject) => {
  db.run(
    "INSERT INTO accounts (username, password, visitorId) VALUES (?, ?, ?)",
    [username, password, visitorId],
    (err) => {
      if (err) reject(err);
      resolve();
    },
  );
});

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6. Test your implementation

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Before you test

1. Install the Fastify CORS plugin:

npm install @fastify/cors

2. Import it in server.js, then register it right after creating your Fastify app:

import cors from "@fastify/cors"; // New
const app = Fastify();
await app.register(cors); // New

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Test the implementation

1. Start your Fastify server:

node server.js

2. In your frontend, trigger a sign-up request that sends the requestId, username, and password to your /api/create-account endpoint. To see the reply messages make sure to parse and display or console log the response from your server.
3. Within your frontend, input a username and password to create a user. Then try to create another user and see that the second attempt will be rejected.
4. Bonus: Try creating an account using a headless browser.

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Next steps

• Node SDK Reference
• Vue frontend quickstart
• API reference for the Events endpoint
• Use case tutorial: Detecting new account fraud
• Low-latency identification with Sealed Client Results