patch
https://api.fuul.xyz/api/v1/referral_codes//use
Increments the usage counter of an referral code and establishes a referral relationship between the user and the code owner. The signature is required to verify ownership of the user identifier.
If the code has a max_uses limit and has already reached it, the request will fail with a 422 error.
Required API Key Scope: referral_codes:read
Message to sign: The message must be exactly "I am using referral code {code}" where {code} is replaced with the actual referral code being used.