Contract Call

What is Contract Call?

A contract call is an interaction with a deployed smart contract to execute its code. It is the mechanism through which users and applications perform actions on a blockchain.

How does Contract Call work?

1. An account (user or another contract) sends a request to a smart contract address.
2. The request specifies a "function selector" and the required input data.
3. If the call only reads data, it is executed locally by a node and costs no gas.
4. If the call modifies the blockchain's state, it must be sent as a transaction and requires a gas fee.
5. The blockchain's virtual machine (e.g., EVM) executes the contract's logic and updates the ledger accordingly.

Why does Contract Call matter?

Contract calls are the fundamental way that users interact with DeFi, NFTs, and DAOs. Every swap on a DEX or mint of an NFT is powered by one or more contract calls, making them the "verbs" of the programmable web.

Key features of Contract Call

• Triggers smart contract logic
• Can be "read-only" or "state-changing"
• Enables complex, automated interactions
• Requires input data (ABI encoded)
• Subject to access control and gas fees

Examples of Contract Call

• Calling the balanceOf function to check a token balance (read-only).
• Calling the transfer function to send tokens to another user (state-changing).
• A DeFi "Zap" that makes multiple contract calls in a single transaction.