101 Smart Contracts and Decentralized Apps in Ethereum

Ethereum is considered to be a blockchain that was conceived in 2013 and was launched in 2015. Ethereum was released to address multiple limitations that exist in Bitcoin. It was designed for allowing short programs’ execution in the blockchain.

Bitcoin focused on decentralized payments, but the other developers wanted better ways for building financial systems following a decentralized path with applications running in the blockchain. We will focus on the smart contract for Ethereum DApps in this article.

Blockchain Smart Contracts | Ethereum Smart Contract Creation
101 Smart Contracts and Decentralized Apps in Ethereum

Smart contracts:

Smart contracts are short programs that the users can run and deploy on the blockchain. It has the potential to hold tokens/funds and state on a ledger and also respond to all the transactions given to it through code execution.

In short, it acts as the state machine and operates in blockchain by having a public address that allows the users to pull or push the state. Such transactions can pass both data and funds.

There are two purposes for making use of smart contracts. The purposes are as follows:

As an example, let us consider a smart contract for betting on sports. A smart contract can be created for storing the bets/funds for a specific game, and also code can be added to distribute the bets when you have got a winner.

From an implementation point of view, EVM (Ethereum Virtual Machine) was designed for running the byte code in the blockchain. This VM is run by each of the nodes present within the network, and any of the arbitrary codes can be executed.

When you create a new smart contract for Ethereum DApps development within a blockchain, it means the representation of the program is sent in byte code as a transaction data payload’s part. As soon as the transaction is run by EV and the block gets added to the ledger, the public address will be received by you when the publication is done. Interaction can be started right from there, having the contract at the particular address.

Three aspects of smart contracts:

The three important aspects of smart contracts are as follows:

Execution context:

Smart Contracts operate within isolation. Only the available data can be seen by the smart contracts on a blockchain or call for any other needful smart contracts. Any calls cannot be made to any of the query data or services from outside.

The contracts are fed by external applications or users with the external data so that they can be consumed by others. A blockchain DApps development company will help you to execute your context right away.


The code that runs in EMV comes up with storage, price, and computing sources, and all these are not for free. Al for utilizing all these services is expressed in gas. It represents Ether’s short representation. For each transaction you submit, gas needs to be paid.

The allocating storage space or code’s executing lines consume gas. In case a transaction is running out of it, it gets canceled, and all the funds/tokens are anyway spent. Remember that gas is not representing a price but a unit.

At the time of the creation of the transaction, the price is assigned by you. A higher price means more priority will be given to the transaction in the queue of execution. The users can fix a limit of gas on a transaction. If your transaction costs more, it will get canceled. Or else, the funds remaining will be backed to you.


Immutability is the nature of smart contracts. And once the byte code is deployed, it cannot be updated or changed on a blockchain. For changing an existing smart contract, a new version must be deployed in the new address.

So, focus on testing and code quality to ensure that you do not introduce bugs that cannot be fixed. Ethereum DApps also share the same nature of immutability of smart contracts.

Decentralized Applications or DApps:

Smart contracts can be considered as back-end APIs that run in blockchain, and the decentralized application in a blockchain can be considered the UX or front-end. The visible layer is represented by the DApps that connect other apps or users with all the smart contracts that run in the blockchain.

Each node that is connected to blockchain releases and RPC-JSON interface over web sockets or HTTPS can be used by any DApp for submitting and connecting transactions.

You need to have a client library in your preferred language that can talk to the interface.

You do not need to run a node to implement DApps or for developing Ethereum DApps. Private offerings can be found inside the cloud that will provide you access to the existing nodes.


The initial proposal of Ethereum was released that enabled apps or users to inject arbitrary code inside the blockchain through transactions. And it was the first time where the smart contracts’ concept was mentioned. Smart contracts and DApps are dependent on each other.

So, whether you develop a front-end or back-end of the applications, you need to make both DApps and Smart contracts work harmoniously. However, for doing so, you may seek professional help from any reckoned DApps development company.



Codezeros is a top Blockchain solution and service provider company that reinvents business with Blockchain solutions.

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Codezeros is a top Blockchain solution and service provider company that reinvents business with Blockchain solutions.