Can blockchain smart contracts interact with the outside world?

No, smart contracts cannot interact with the world outside of the blockchain on which they live. For example, a smart contract cannot act as a REST endpoint or data source. Smart contracts can interact with other contracts in the same environment, or with compatible external libraries. When creating an external library to interact with a Casper smart contract, consider the following:

• Wasm is expressed as little-endian by default. Check for endianness compatibility.
• As wasm32-unknown-unknown is a 32-bit platform, it cannot support 64-bit external code. Your library needs to be compatible with 32-bit code.
• Consider a library that supports no_std.
• Try to avoid native operating system calls. If the library uses the filesystem, sockets, or other native OS functionality, then it may not work with a Casper smart contract.

If you have any concerns, questions, or issues, please submit a request to our support team here:

https://support.casperlabs.io/hc/en-gb/requests/new