You can get your API key set from Google ReCaptcha.
Enable and Set-up
To enable ReCaptcha, you need to set those keys in your environment:
RECAPTCHA_PUBLIC_KEYto your public/ site API key;
RECAPTCHA_PRIVATE_KEYto your secret/ private API key.
You are not required to set your public and private keys for development use. You can use the following development keys:
You only have to set them up if you are using Saleor for production (Google will remind you if you do not).