A buyer can be deleted by calling the DELETE /buyers/{buyer_id} API.
Although this API deletes the buyer resource, it does not delete any associated payment methods and transactions. Instead, it only disassociates these from the buyer resource.
curl -i -X DELETE "https://api.example.gr4vy.app/buyers/77a76f7e-d2de-4bbc-ada9-d6a0015e6bd5" \
    -H "Authorization: Bearer [JWT_TOKEN]"
The API returns an empty response once the buyer was deleted.