Thanks for reaching out. You can use the API with OAuth1.0 without IP restrictions.
To better secure OAuth 2.0 we have implemented IP Restrictions, which 'white list' IP Addresses for a given client Key/Secret.
We block requests to fatsecret API for a Key/Secret if the source IP is not white listed. Before releasing these IP ranges we allowed only 15 specific IP addresses, now we allow up to 15 ranges of IP addresses in your account under "Manage API Keys".
Example (recommended for your use case described above):
0.0.0.0/0 => is a range that allows any IPV4
https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing For Mobile apps we would recommend using an API proxy server to avoid Mobile Apps communicating directly with fatsecret APIs.
This proxy should be responsible for:
- Managing the validity / renewal of your OAuth 2.0 access tokens
- Forwarding any fatsecret related requests to fatsecret APIs
Please avoid having your client's credentials part of your Mobile App source code / configuration.