Fidro + Express.js Integration

Middleware-ready fraud detection for Express. Follow this guide to add email validation and IP intelligence in minutes.

Overview

To integrate Fidro with Express.js, use the built-in fetch API (or node-fetch) to send a POST request to the Fidro API as middleware. Fidro returns email validation results, disposable email detection, IP intelligence, and a fraud risk score that you can attach to the request object. The integration works as Express middleware, so you can protect specific routes or your entire application with automatic fraud detection — no SDK required.

Fidro is a fraud detection API that combines email validation, IP intelligence, geolocation analysis, and Stripe chargeback prevention in a single API call. It returns a risk score with a clear recommendation — allow, review, or block — so you can stop fraud without building your own scoring logic.

1. Install Dependencies

# Node 18+ has built-in fetch. For older versions:
npm install node-fetch

You will also need a Fidro API key. Sign up for free to get one.

2. Email Validation

Send a POST request to Fidro's /v1/validate endpoint with the user's email address and optional IP. Fidro validates the email, checks for disposable domains, analyzes the IP for VPN/proxy/Tor usage, and returns a risk score with a clear recommendation — allow, review, or block.

// middleware/fidro.js
const FIDRO_API_KEY = process.env.FIDRO_API_KEY;

async function fidroValidate(req, res, next) {
  const email = req.body.email;
  if (!email) return next();

  const ip = req.headers["x-forwarded-for"] || req.socket.remoteAddress;

  try {
    const response = await fetch("https://api.fidro.io/v1/validate", {
      method: "POST",
      headers: {
        Authorization: `Bearer ${FIDRO_API_KEY}`,
        "Content-Type": "application/json",
      },
      body: JSON.stringify({ email, ip }),
    });

    if (!response.ok) {
      console.error(`Fidro API error: ${response.status}`);
      return next(); // Fail open — don't block on API errors
    }

    const result = await response.json();
    req.fidro = result.data;

    if (result.data.recommendation === "refund") {
      return res.status(403).json({ error: "Request flagged as fraudulent" });
    }

    next();
  } catch (err) {
    console.error("Fidro error:", err.message);
    next(); // Fail open
  }
}

// ----- Express app example -----
// app.js
const express = require("express");
const app = express();

app.use(express.json());

// Apply to specific routes
app.post("/api/signup", fidroValidate, (req, res) => {
  console.log("Risk score:", req.fidro?.risk_score);
  console.log("Recommendation:", req.fidro?.recommendation);

  // Continue with signup logic...
  res.json({ success: true, risk_score: req.fidro?.risk_score });
});

app.listen(3000, () => console.log("Server running on port 3000"));

3. IP Lookup

Send a POST request to Fidro's /v1/ip-lookup endpoint with an IP address. Fidro returns geolocation data (country, city, ISP), VPN and proxy detection, Tor exit node identification, and threat intelligence — all in a single API call.

const FIDRO_API_KEY = process.env.FIDRO_API_KEY;

async function fidroIPLookup(req, res, next) {
  const ip = req.headers["x-forwarded-for"] || req.socket.remoteAddress;

  try {
    const response = await fetch("https://api.fidro.io/v1/ip-lookup", {
      method: "POST",
      headers: {
        Authorization: `Bearer ${FIDRO_API_KEY}`,
        "Content-Type": "application/json",
      },
      body: JSON.stringify({ ip }),
    });

    if (!response.ok) {
      console.error(`Fidro API error: ${response.status}`);
      return next();
    }

    const result = await response.json();
    req.fidroIP = result.data;
    next();
  } catch (err) {
    console.error("Fidro error:", err.message);
    next();
  }
}

// Usage in Express
app.get("/api/check-ip", fidroIPLookup, (req, res) => {
  res.json({
    country: req.fidroIP?.country,
    is_vpn: req.fidroIP?.is_vpn,
  });
});

Next steps

Explore the full API reference, try the free email checker, or see how Fidro compares to other solutions.

API Documentation Free email checker Compare Fidro

Frequently Asked Questions

How do I add fraud detection to Express.js?

You can add fraud detection to Express.js by creating middleware that calls Fidro's REST API with a POST request containing the user's email and IP address. Fidro returns a risk score and a clear recommendation — allow, review, or block. The entire integration takes about 5 minutes and works as drop-in middleware.

Does Fidro have an Express.js SDK?

Fidro doesn't require an SDK. It's a standard REST API that works with Node.js's built-in fetch API (Node 18+) or the node-fetch package. You can write a simple middleware function that handles the API call and attaches the result to the request object.

Is Fidro free to use with Express.js?

Yes, Fidro offers a free plan with 1,000 validations per month, no credit card required. It works with any Express.js application, whether you're building a REST API, web app, or microservice.

Start catching bad signups in the next 5 minutes

Create your account, grab your API key, and send your first request. Free plan with 200 validations/month. No credit card. Cancel anytime.

Get Started Free