How Does a Contract Manage Multiple Simultaneous External Calls?

The EVM processes transactions sequentially within a block, meaning that from the perspective of the blockchain, there are no truly simultaneous external calls. However, within a single transaction, a contract can initiate multiple external calls.

These are managed by the execution flow, which executes the calls one after the other. If the contract is designed to handle multiple asynchronous interactions, it must use state variables to track the status of each sub-call to ensure that the overall state remains consistent after all calls return.