Making HTTP requests

Advanced

Concept

Overview

Canister smart contracts can make a request to a URL using HTTPS outcalls. HTTPS outcalls can be used to directly obtain off-chain data or interact with off-chain systems, such as Web 2.0 services or enterprise IT infrastructure.

HTTPS outcalls enable a wide range of applications. For example, oracle services can directly integrate with ICP in a trustless manner, and dapps can provide user notifications or anything else that requires communication with servers on the Internet.

How it works

For detailed information on how it works, please refer to the HTTPS outcalls - How it works.

How to make a request

For detailed information on how to utilize this feature, please refer to the HTTPS outcalls - How to use page.

The documentation includes examples demonstrating how to make the following types of requests:

• GET Request
• POST Request

Examples

Refer to the following examples of HTTP outcalls implementations in canister smart contracts:

• Fetch price information for DeFi protocols using the Exchange Rate Canister.
• Communicate with other chains using the EVM RPC Canister.
• Fetch information about Bitcoin Ordinals and Bitcoin Meta-Protocols using the Ordinals Canister.