Introduction
Signum has two separate APIs. One exists for the wallet apps to communicate with, and the other is for the nodes to talk with each other. This documentation refers to them as the Wallet or Web API, and the Peer to Peer or P2P API.
Wallet / Web API
The Wallet API is designed for wallet software and only has Denial of Service (DoS) protections enabled. Other than an attack, it is safe to make requests to any number of times, and unlike the P2P API, it will not blacklist your client. The primary purpose of this API is to allow the management of individual Signum accounts, sending and receiving transactions, and other user tasks.
Peer to Peer (P2P) API
The Peer to Peer API is primarily designed for nodes to talk with each other, though it can be used to get certain information that may not be readily available via the wallet API. This should be done sparingly, however, as the node software is designed to automatically black list IP addresses making incorrect requests, or spamming the API.