TrustCaptcha – Bot protection

Express CAPTCHA Integration

Wire TrustCaptcha into an Express route or middleware in just a few lines of Node.js. Stop bot-driven spam on logins, signups and contact forms — without breaking your existing body parsers or CSRF setup. EU-hosted, GDPR-ready, no image puzzles.

Quickstart

How the integration works

1. Create a CAPTCHA

Create a user account or log in with an existing one. Then create a new CAPTCHA or select an existing one. If you’re unsure whether TrustCaptcha is right for you, try our CAPTCHA service risk-free for 14 days at no cost.

On the CAPTCHA overview page, you will find all the important information, such as the site key and licence key, and you can also create your API key. Allow your websites to access your CAPTCHA by simply adding them to the access authorised domain list in the CAPTCHA security rules.

CAPTCHA security rules of a demo CAPTCHA.

2. Add the CAPTCHA widget to your form

Drop the TrustCaptcha widget into the HTML form your Express route serves. The widget runs the CAPTCHA in the background and adds a hidden tc-verification-token field on submit, which arrives on req.body like any other input.

contact.html

HTML

<script type="module" src="https://cdn.trustcomponent.com/trustcaptcha/3.0.x/trustcaptcha.esm.min.js"></script>

<form method="post" action="/contact">
    <input type="email" name="email" required>
    <trustcaptcha-component sitekey="<your_site_key>"></trustcaptcha-component>
    <button type="submit">Send</button>
</form>

The CAPTCHA widget will then be displayed inside your form:

Need detailed information about the CAPTCHA widget integration?
For the full widget reference — including themes, languages, custom design and more — please read our documentation.

Read the documentation

3. Validate the token in your Express route

In your Express route handler, take the verification token from req.body, look up the result via our Node.js library, and decide whether to accept the request.

First, install our TrustCaptcha Node.js library:

Install

bash

npm i @trustcomponent/trustcaptcha-nodejs

Then validate the token inside your Express route and act on the result:

server.ts

TypeScript

import express from "express";
import { TrustCaptcha } from "@trustcomponent/trustcaptcha-nodejs";

const app = express();
app.use(express.urlencoded({ extended: true }));

app.post("/contact", async (req, res) => {
  const token = req.body["tc-verification-token"] ?? "";

  try {
    const result = await TrustCaptcha.getVerificationResult("<your_api_key>", token);
    if (!result.verificationPassed || result.score > 0.5) {
      return res.status(400).send("CAPTCHA verification failed.");
    }
  } catch {
    return res.status(400).send("CAPTCHA verification failed.");
  }

  // CAPTCHA passed — process the request
  res.send("Thanks!");
});

Need detailed information about the Express CAPTCHA integration?
For full step-by-step instructions — including a reusable middleware refactor — please read our documentation.

Read the documentation

Other backend framework instead of Express?
If you use a different framework, pick the matching recipe here. If your framework isn’t listed, your software developers can integrate the verification themselves using our documentation or ask our support team for a pre-built integration.

4. Congratulations 🎉

You are now protected by TrustCaptcha - congratulations!

FAQs

Where in an Express app does the CAPTCHA verification go?

Inside the route handler that receives the form submission, before you persist data or send any email. The CAPTCHA token comes in as a regular form field on req.body (default name: "tc-verification-token"), so you can read it like any other input.

Do I need to register a body parser?

Yes. The CAPTCHA token lives on req.body, so make sure express.urlencoded() or express.json() is registered before the route or middleware that reads it. Without a body parser, req.body is undefined and the verification always fails.

Can I run the CAPTCHA verification as Express middleware?

Yes — and that's the cleanest way once you protect more than one route. Build a small async middleware that reads the token from req.body, verifies it via the Node.js library, and calls next() on success. You can attach it per route or to a whole router prefix.

Does TrustCaptcha replace my existing CSRF protection (csurf, lusca, …)?

No. TrustCaptcha and CSRF are independent layers — both should stay enabled. The CAPTCHA token only confirms that a human filled the form; it does not protect against cross-site request forgery.

Where should I store the CAPTCHA API key?

In an environment variable (e.g. process.env.TRUSTCAPTCHA_API_KEY). Load it from a .env file in development and from your hosting provider's secret store in production. Never commit the key to your repo.

Losing leads to CAPTCHAs?

TrustCaptcha blocks spam and bots, not customers. No puzzles, GDPR-ready, EU-hosted.

Puzzle-free UX

Runs in the background while visitors type — so more people finish your forms and fewer drop off.

GDPR-ready

EU-hosted and privacy-first: no cookies, encrypted transmission, automatic cleanup — with ready-to-use legal resources.

Multi-layer Security

Adaptive protection plus intelligent risk scoring stops abuse early — even when attack traffic spikes.

Full Control

Fine-tune sensitivity, set allow/block lists, and use geoblocking — you decide how strict verification should be.

Protect your Express application with TrustCaptcha in just a few steps!

EU-hosted & GDPR-ready
No puzzles
Try free for 14 days

Get started Contact sales