No-Code Smart Contract Interaction & Coding a PancakeSwap-Like Swap Function

Blockchain technology continues to democratize access to decentralized finance (DeFi), and one of the most empowering aspects is the ability to interact with smart contracts—with or without coding experience. Whether you're a beginner exploring Web3 or a developer building DeFi tools, understanding how to exchange tokens through smart contracts is essential. This guide walks you through two practical approaches: performing token swaps without writing code, and coding your own swap function similar to PancakeSwap using Ethereum's Uniswap V2 router.

All examples use the Rinkeby test network, allowing you to experiment risk-free.

Why Interact with Smart Contracts?

Smart contracts power most DeFi applications, from decentralized exchanges (DEXs) like Uniswap and PancakeSwap to lending platforms and NFT marketplaces. Interacting directly gives you full control over your assets and transactions—bypassing intermediaries and gaining deeper insight into how blockchain applications work.

You don’t need to be a developer to get started. Even non-coders can call contract functions via blockchain explorers. For those who want more automation or customization, coding offers full flexibility.

Core Keywords

Smart contract interaction
No-code blockchain
Token swap
WETH (Wrapped ETH)
Uniswap V2 router
ERC-20 standard
Decentralized exchange (DEX)
Web3 development

These keywords reflect both beginner-friendly exploration and technical implementation, aligning with search intent for users learning about DeFi interactions.

Case 1: No-Code Token Swap – Convert ETH to WETH

What Is WETH?

WETH stands for Wrapped ETH, an ERC-20 compatible version of native Ethereum (ETH). While ETH is the base currency of the Ethereum network, it predates the ERC-20 token standard and doesn’t fully comply with it. This creates compatibility issues when using ETH in DeFi protocols that expect ERC-20 tokens.

By wrapping ETH into WETH, you enable seamless integration with decentralized exchanges, lending platforms, and other smart contracts that require ERC-20 compliance.

👉 Discover how to wrap ETH and start interacting with DeFi protocols today.

How to Deposit ETH and Mint WETH (No Code)

You can perform this operation directly on Rinkeby Etherscan, a blockchain explorer for the Ethereum testnet.

Visit the WETH contract address on Rinkeby:
0xc778417e063141139fce010982780140aa0cd5ab
Navigate to the "Contract" tab → "Write Contract"
Connect your wallet (e.g., MetaMask)
Find the deposit() function and click "Write"
Specify the amount of ETH you want to wrap (in ETH, not wei)
Confirm the transaction in your wallet

Once confirmed, you’ll receive an equal amount of WETH. This newly minted WETH can now be used in any ERC-20-compatible DeFi application.

This method requires zero coding—perfect for beginners testing how smart contracts work.

Case 2: Code Your Own Token Swap – Mimic PancakeSwap Functionality

While PancakeSwap operates on Binance Smart Chain, its mechanics mirror those of Uniswap on Ethereum. Both use automated market makers (AMMs) and shared liquidity pools. You can replicate core functionality—like swapping ETH for DAI—using Uniswap’s V2 router contract.

We’ll walk through a Node.js script that calls swapExactETHForTokens, one of the most commonly used functions in DeFi.

Step 1: Gather Required Information

Before coding, collect the following:

Uniswap V2 Router Address (Rinkeby):
0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D
WETH Contract Address:
0xc778417E063141139Fce010982780140Aa0cD5Ab
DAI Testnet Contract Address:
0x5592EC0cfb4dbc12D3aB100b257153436a1f0FEa
Your Wallet Address (recipient)
Slippage Tolerance & Deadline: Prevent failed transactions due to price volatility

Step 2: Retrieve ABI from Blockchain Explorer

The Application Binary Interface (ABI) defines how your code interacts with a smart contract.

Go to the Uniswap V2 Router on Rinkeby Etherscan
Scroll down and click "Contract ABI"
Copy the JSON and save it as uniswap.json in your project folder

Step 3: Write the Swap Script

Below is a complete Node.js script using Web3.js to execute a swap:

const Web3 = require('web3');
const web3 = new Web3('https://rinkeby.infura.io/v3/YOUR_INFURA_PROJECT_ID');

const fs = require('fs');
const path = require('path');
const filePath = path.join(__dirname, './uniswap.json');
const jsonfile = JSON.parse(fs.readFileSync(filePath, 'utf8'));
const abi = JSON.parse(jsonfile.result);

const privateKey = 'your_private_key'; // Never expose this
const account = web3.eth.accounts.privateKeyToAccount(privateKey);
web3.eth.accounts.wallet.add(account);

const amountEth = web3.utils.toWei('0.01', 'ether'); // Amount to swap
const amountOutMin = 0; // Set based on slippage tolerance
const path = [
  '0xc778417E063141139Fce010982780140Aa0cD5Ab', // WETH
  '0x5592EC0cfb4dbc12D3aB100b257153436a1f0FEa'  // DAI
];
const to = 'your_wallet_address';
const deadline = Math.floor(Date.now() / 1000) + 60 * 20; // 20 minutes

async function swapETHForDAI() {
  const contract = new web3.eth.Contract(abi, '0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D');

  const tx = await contract.methods.swapExactETHForTokens(
    amountOutMin,
    path,
    to,
    deadline
  ).send({
    from: account.address,
    value: amountEth,
    gas: 250000,
    gasPrice: await web3.eth.getGasPrice()
  });

  console.log('Transaction Hash:', tx.transactionHash);
}

swapETHForDAI();

After running this script, you’ll receive DAI in your wallet—just like using PancakeSwap or Uniswap manually.

👉 Learn how to securely manage private keys and deploy DeFi interactions safely.

Frequently Asked Questions (FAQ)

Can I interact with smart contracts without coding?

Yes! Blockchain explorers like Etherscan allow you to connect your wallet and call read/write functions directly in the browser—no code needed.

Is WETH safe to use?

Absolutely. WETH is a well-audited, widely adopted standard. Wrapping and unwrapping are reversible and transparent processes.

Why do I need WETH instead of ETH?

Most DeFi protocols require ERC-20 compatibility. Since native ETH isn’t ERC-20 compliant, WETH acts as a bridge, enabling participation in liquidity pools, swaps, and lending.

What is slippage, and why set `amountOutMin`?

Slippage accounts for price changes during transaction processing. Setting amountOutMin ensures you receive at least a minimum amount of tokens—or the transaction reverts.

Can I use this code on mainnet?

Yes, but replace testnet addresses with their mainnet equivalents and ensure proper security practices (e.g., environment variables for private keys).

Does this work on Binance Smart Chain?

The logic is identical, but you’d use PancakeSwap’s router address and BSC network endpoints instead of Uniswap and Ethereum.

Final Thoughts

Whether you're swapping ETH for WETH via a blockchain explorer or writing code to automate complex DeFi trades, the tools are accessible. The key is understanding the underlying mechanics: smart contracts, token standards, and decentralized routing logic.

As DeFi evolves, these skills become increasingly valuable—not just for developers, but for all participants in the Web3 ecosystem.

👉 Start practicing smart contract interactions securely with trusted tools today.