The way we sell and purchase digital assets, as well as trade them, has changed because of blockchain technology. New types of trading have been made available to people through decentralized exchanges (DEXs) as a way to purchase and sell assets without having to rely on a third party.

In addition, automated ways to settle transactions based on predetermined criteria, such as using smart contracts, are an essential component of decentralized exchanges such as Uniswap, PancakeSwap, and SushiSwap.They allow for fast, efficient, and secure transactions on those platforms; all executed by smart contracts without any need for third-party verification or trust.

What Are Smart Contracts?

In order to be eligible to participate actively in decentralized trading and/or to build your own DEX, you must know how to work with smart contracts. Specifically, you will want to understand how they operate and what role they play in executing trades on the blockchain via DEX platforms.

Ultimately, while the construction of smart contracts is relatively simple, their implementation and operational functioning within DEX platforms is complex. In addition, smart contracts have a critical role in fostering an environment of trust between the parties involved by creating an immutable electronic representation of their agreement. Once an agreement has been executed via a smart contract, it cannot ever be modified or cancelled.

Smart contracts allow for the accomplishment of all actions in the series of actions needed to execute a trade on a blockchain without resorting to or relying upon the services of a centralized authority. Consequently, by eliminating the need for a central authority, confidence will be established in these trades, and their validity and integrity will not be subject to fraud or manipulation during their execution.

Role of Smart Contracts in Decentralized Exchanges

Smart contracts fulfill the role of brokers, order books, and custodians by performing tasks related to the execution of trades, the provision of liquidity, the holding of funds in custody, and the payment of fees using smart contracts instead of using traditional methods of performing these functions.

Once a user has submitted a trade request to a smart contract, the smart contract will interact with the user to determine if the user has a current open order, calculate the price of the token being exchanged, complete the exchange of tokens, and update the user's account. This will all happen within seconds after the user submits their request.

Step-by-Step - How Smart Contracts Work in a DEX?

User Connects Wallet

A user will connect their wallet (e.g. via Metamask or Trust Wallet) to the DEX interface to allow the smart contract to access the user's public key and begin executing the user's trade.

Trade Request is Initiated

This is initiated by the user selecting the tokens to be swapped and entering the amount to be swapped; the trade request is sent to the smart contract by means of the DEX interface.

Smart Contract Checks Liquidity

The smart contract will check the available items in the pool to confirm that there is sufficient liquidity to carry out the trade; if the answer is yes, the transaction will continue to the next step.

Price Calculation via AMM

Though most DEXs rely on Automated Market Makers or AMMs rather than order books, the market price is determined by the algorithmic calculation of token prices through the use of a constant product formula (for example, x * y = k).

Transaction Approval

Once users approve a transaction through their wallets, AMM smart contracts can now access their tokens and complete the transaction.

Trade Execution

When users approve the trade, AMM protocols quickly complete the trade by swapping tokens from liquidity pools and depositing them into the user’s wallet.

Fee Distribution

INO Scenario  Fees will be deducted from the sale, which in turn will be distributed to liquidity providers as payment for providing liquidity in the pool.

Blockchain Confirmation

All transactions are recorded on the blockchain and stored in an immutable and fully transparent format.

Key Components of Smart Contracts in DEXs

Liquidity Pools

In place of matching buyers and sellers directly, users of a DEX provide liquidity by contributing to a Liquidity Pool that is governed and monitored by AMM smart contracts.

Automated Market Makers (AMMs)

AMMs are algorithms embedded into smart contracts that help to set token prices based on the laws of supply and demand.

Token Swapping Mechanism

AMM smart contracts enable users to swap tokens directly with other users by executing an automated token swap process with the liquidity pool.

Fee Mechanism

AMMs automatically calculate and disburse trading fees to liquidity providers out of all transactions completed through their AMM protocol.

Security Protocols

To help prevent hacking of the AMM, AMM smart contracts are equipped with security features such as reentrancy checks and validation protocols.

Benefits of Smart Contracts in DEXs

Trustless Trading

The use of Smart Contracts cuts down on the need for middlemen, allowing automated trades to automatically execute trades without third-party intervention when predetermined conditions are met, in effect providing the user with a secure method of trading without reliance on another entity (3rd party).

Transparency

Transparency of all Transactions and Trades via Blockchain Technology, additionally every Transaction and trade can be verified by any parties interested in verifying them. This creates trust in the ability of a user to perform an audit independently.

Security

Security of all funds held in a user’s Wallet remains secure until the trade is completed and Approved (A.K.A. Executed), thus eliminating any chance of being hacked via central Exchange transactions. Furthermore, the advanced logic associated with the smart contracts adds additional layers of protection against fraud.

Automation

Automation of the entire process (from calculating price to executing trade) greatly reduces delays (due to human interactions), eliminates human error, and thus reduces the risk for Operational Inefficiencies associated with closing out trades.

Global Access 

Anyone with an internet connection + crypto wallet will have access to a DEX platform and is not limited or restricted by their location; therefore creates additional Financial Opportunities for its users.

Challenges of Smart Contracts in DEXs

Smart Contract Vulnerabilities

Bugs or glitches in the Smart Contract code may allow an Attacker to exploit a vulnerability in the Smart Contract and cause loss of user funds. Repairing bugs/glitches in a Smart Contract once deployed can be a long process and costly.

High Gas Fees

Gas Costs on public Blockchains such as Ethereum may become quite expensive during times of Peak Volume, therefore resulting in discouraging Small Traders from using DEX.

Slippage Issues

If the volume of a Trade executed on the DEX exceeds the liquidity available in that specific token Pool, it may create a significant impact on the price of the token; therefore, resulting in less favourable rates than anticipated by the end-user.

Complexity for Beginners

In order to successfully use a DEX, a user must have at least a basic understanding of how to use a wallet, what a private key is, and what are gas fees; this can create challenges for someone who has just entered the cryptocurrency ecosystem.

Real-World Examples

Uniswap, PancakeSwap and SushiSwap are three platforms that demonstrate how the efficiency of smart contracts has enabled the development of fully decentralized trading ecosystems.

Future of Smart Contracts in DEXs

The development of decentralized exchanges will be linked to the continuing evolution of smart contract technology. The continued development of smart contract implementation with layer-2 scaling solutions, cross-chain interoperability, and AI-driven trading capabilities will greatly improve both performance and usability.

As the adoption of decentralized finance (DeFi) continues to increase, smart contracts will continue to evolve, thereby providing enhanced security, scalability and features for users when using decentralized trading solutions.

Conclusion

Smart contracts are fundamentally the underlying technology driving DEX’s as they provide secure, efficient and automated trading without the need for a middleman. Smart contracts are responsible for bringing about liquidity, performing trades and providing trustless transactions and have forever transformed the way that we trade digitally in crypto.

As we continue to see advancements in blockchain technology (e.g. layer-2 with Ethereum 2.0) as well as in the decentralisation of traditional financial services, smart contracts will further pave the way towards decentralised finance by providing better access and efficiency for all users globally when performing trades through DEX’s.