Angular Widget集成Google reCAPTCHA：无域名注册等技术问询

Hey there! Let's walk through each of your questions clearly, since you're building an Angular widget that gets embedded across multiple sites (both via JavaScript and iframe):

1. Do I need to register a domain to integrate reCAPTCHA? #

It depends on which version of reCAPTCHA you're using:

• Standard reCAPTCHA v2/v3: Yes, you must register allowed domains when creating site/secret keys in the Google Cloud Console. You can use wildcards (like *.example.com) for a range of subdomains, but you can't skip specifying domains entirely—Google checks the request's origin domain against this list to prevent misuse.
• reCAPTCHA Enterprise: If your widget needs to work on any third-party site (no fixed domain scope), this is the right choice. Enterprise's score-based keys don't require domain binding, making them ideal for embedded widgets that live across multiple external sites.

2. Can I skip server-side validation of the reCAPTCHA token? #

Short answer: No, you can't—and you shouldn't.
The token you get from angular-recaptcha on the frontend is just a client-side assertion. Skipping server-side validation would let malicious users easily fake valid tokens, completely defeating the purpose of reCAPTCHA. You must use your secret key to call Google's validation API from your backend to verify that the token is legitimate, tied to the correct site, and hasn't been tampered with. This is a core security requirement for reCAPTCHA, regardless of the version you're using.

3. Are there any licensing requirements? #

Absolutely, here's what you need to know:

• Standard reCAPTCHA (free): You must comply with Google's reCAPTCHA Terms of Service. This includes not modifying the reCAPTCHA widget, properly disclosing to users that you're using reCAPTCHA, and adhering to data privacy rules (like GDPR, since reCAPTCHA collects user data for validation).
• reCAPTCHA Enterprise: This is a paid service, and you'll need to agree to Google's Enterprise Terms of Service. It's designed for high-traffic use cases, advanced security features, and scenarios like your cross-site widget.
  Additionally, if your widget is embedded on sites that fall under specific regional privacy laws, you'll need to ensure your use of reCAPTCHA aligns with those regulations (e.g., getting user consent where required).

内容的提问来源于stack exchange，提问作者Srivi