You may hear the word “gas fees” whether you are a developer, a user, or a newbie to the blockchain world. It’s a small amount of cryptocurrency required to be paid in order to execute a transaction or execute a smart contract on the Ethereum blockchain.

We know that gas fees can fluctuate, which means the total price depends on many factors, and the most common one you may hear is based on the network traffic. However, this article is not going to teach you how to save your money as a trader in the blockchain market, but give you and also me a taste of those factors from a developer’s perspective.

The most basic factors affecting gas fees of deploying or executing a smart contract are similar to those concepts we develop for Web2 services. The bundle sizes, the complexity of calculation, and the storage operations are all factors. The biggest difference between Web2 App and a smart contract is the performance issues. You can optimize your coding and querying, but we have no silver bullet to solve the traffic problems depending on the current conditions of the Ethereum Network. However, we still can have awareness of these common factors.

If we want to deploy a smart contract on Ethereum Network, we need to compile it to generate the bytecode and ABI.

Like we deploy our bundle to a deployment service site, the larger file we have, the more amount of bandwidth will be consumed due to more data transferred over the network.

But what makes the compiled files larger? It depends on specific implementations of a smart contract.

The number of computations performed by the contract

You may not be unfamiliar with the concept of time and space complexity. This surely affects the gas fees since it takes more computation which leads to more gas to get the mathematical calculation done. A nested for-loop function is definitely more complex than simple a+b.

The number of storage operations

Having more processes of writing and reading from storage will require more gas. This concept is similar to querying data from an SQL database. However, Blockchain is a P2P network with a decentralized network of nodes. In other words, if we modify the state variables in a smart contract, it will take a miner to have PoW to get the process done. After the work is completed, the ledger of every node will have this record of the storage operation. Therefore, storage operations may sometimes be more expensive in terms of gas usage than having more computations.

The proper data types of state variables

As we know the concept of storing our data in a dataset, different types of values will have different storage requirements. Here is an article naming a few types in Solidity. More efficient usage of data structure can save the storage requirements.

External calls of other smart contracts or addresses

A deployed smart contract in Ethereum Network will have its unique address start with “0x”. We can have interactions between different smart contracts and addresses with a lot of effort contributed by Ethereum Virtual Machine (EVM) on every node in the Ethereum Network.

1. Verify the address and the code of the target contract.
2. Ensure that the call is valid and authorized.
3. Handle the transfer of data, value, and response errors between the contracts.

When we have another external contract or address, it requires additional code to be included in the compiled file to handle the interaction.

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