Migrate from reCAPTCHA

This guide walks through swapping Google reCAPTCHA for ALTCHA — updating the widget on your forms and the verification call on your server.

Why switch

	reCAPTCHA	ALTCHA
No cookies or tracking scripts	No	Yes
Verifies locally, no remote API call	No	Yes
Self-hosting option	No	Yes
Open-source, auditable code	No	Yes
Data residency control	No	Yes

The "no remote API call" difference is a practical one, not just a privacy one: reCAPTCHA requires your server to call Google's siteverify endpoint on every submission, adding a network round-trip and an external dependency to your request path. ALTCHA's libraries verify the payload cryptographically, in-process — see Server Verification.

Pick how you'll host it

Just want it running today, for free — use the open-source widget with your own server. See Quick Start.
Don't want to run any infrastructure — use ALTCHA Cloud, fully managed and hosted in the EU.
Need the full adaptive-protection platform on your own infrastructure — use ALTCHA Sentinel.

All three use the same <altcha-widget> element and the same verification libraries — you can start with the open-source core and move to Cloud or Sentinel later without changing your integration.

Before (reCAPTCHA):

<script src="https://www.google.com/recaptcha/api.js" async defer></script>

<form action="/submit" method="POST">
  <div class="g-recaptcha" data-sitekey="YOUR_SITE_KEY"></div>
  <button type="submit">Submit</button>
</form>

After (ALTCHA):

<script async defer src="https://cdn.jsdelivr.net/gh/altcha-org/altcha/dist/main/altcha.min.js" type="module"></script>

<form action="/submit" method="POST">
  <altcha-widget challenge="https://your-challenge-url"></altcha-widget>
  <button type="submit">Submit</button>
</form>

See Widget Integration for npm installs and framework-specific setup (React, Vue, Svelte, and others).

Update server-side verification

Replace the call to Google's siteverify endpoint with a local, cryptographic check using an official library:

Using your own server → verifySolution
Using Cloud or Sentinel → verifyServerSignature

Migration checklist

Remove the reCAPTCHA script tag, data-sitekey, and secret key.
Add the <altcha-widget> element in its place.
Point challenge at your chosen setup — your own server, Cloud, or Sentinel.
Swap the siteverify call for a local verification call.
Test: submit without solving (should be rejected), then submit normally (should succeed).

Next steps

Quick Start — full integration walkthrough
Widget Integration — configuration and framework installs
Server Integration — verification libraries