The digital advertising industry is undergoing a significant transformation, driven by emerging technologies like blockchain and the increasing demand for interactive ad campaigns. In this article, we’ll explore the architecture of a decentralized that leverages blockchain technology to deliver interactive ads with rewards in the form of ERC-20 tokens and NFTs. We’ll dive deep into the technical details and provide examples of Python and Solidity code to help you understand the inner workings of this next-generation DSP. Demand Side Platform (DSP) Smart Contract Interaction The foundation of our decentralized DSP is a set of smart contracts that manage ad campaigns, user rewards, and . NFT minting Here’s a simple example of a Solidity smart contract for managing ad campaigns: pragma solidity ^0.8.0; contract AdCampaign { struct Campaign { uint256 id; address advertiser; string ipfsHash; uint256 budget; uint256 reward; bool isActive; } uint256 private campaignCounter; mapping(uint256 => Campaign) public campaigns; function createCampaign(string memory ipfsHash, uint256 budget, uint256 reward) public { campaignCounter++; campaigns[campaignCounter] = Campaign(campaignCounter, msg.sender, ipfsHash, budget, reward, true); } function toggleCampaignStatus(uint256 campaignId) public { require(campaigns[campaignId].advertiser == msg.sender, "Not the owner of the campaign"); campaigns[campaignId].isActive = !campaigns[campaignId].isActive; } } To interact with these smart contracts using Python, we’ll use the popular . Web3.py library Here’s an example of how to create a new ad campaign using the smart contract above: from web3 import Web3 # Connect to the Ethereum node w3 = Web3(Web3.HTTPProvider('<YOUR_ETHEREUM_NODE_URL>')) # Load the contract ABI and address contract_abi = [...] # Contract ABI goes here contract_address = '0x123...' # Initialize the contract object contract = w3.eth.contract(address=contract_address, abi=contract_abi) # Define the advertiser's account advertiser_account = w3.eth.account.privateKeyToAccount('<YOUR_PRIVATE_KEY>') # Create a new ad campaign ipfs_hash = 'QmWATWQ7fVPP2EFGu71UkfnqhYXDYH566qy47CnJDgvs8u' budget = 1000 reward = 10 # Estimate gas gas_estimate = contract.functions.createCampaign(ipfs_hash, budget, reward).estimateGas({'from': advertiser_account.address}) # Send the transaction transaction = contract.functions.createCampaign(ipfs_hash, budget, reward).buildTransaction({ 'from': advertiser_account.address, 'gas': gas_estimate, 'gasPrice': w3.eth.gasPrice, 'nonce': w3.eth.getTransactionCount(advertiser_account.address) }) signed_transaction = advertiser_account.signTransaction(transaction) transaction_hash = w3.eth.sendRawTransaction(signed_transaction.rawTransaction) Decentralized Storage To store ad content and metadata, we’ll use , a decentralized storage system. IPFS (InterPlanetary File System) In Python, we can use the library to add and retrieve content from IPFS: ipfshttpclient import ipfshttpclient client = ipfshttpclient.connect('/ip4/127.0.0.1/tcp/5001/http') # Add a file to IPFS with open('ad_content.json', 'rb') as f: result = client.add(f) ipfs_hash = result['Hash'] # Retrieve content from IPFS content = client.cat(ipfs_hash) User Targeting and Data Integration For user targeting, we’ll need to access both on-chain and off-chain data. To interact with on-chain data, we can use Web3.py, as demonstrated earlier. For off-chain data, we can use a decentralized oracle solution like Chainlink. Here’s an example of a Solidity contract that interacts with Chainlink to fetch off-chain data: pragma solidity ^0.8.0; import "@chainlink/contracts/src/v0.8/ChainlinkClient.sol"; contract AdDataOracle is ChainlinkClient { uint256 public adPerformance; address private oracle; bytes32 private jobId; uint256 private fee; event AdPerformanceUpdated(uint256 performance); constructor(address _oracle, bytes32 _jobId, uint256 _fee) { setPublicChainlinkToken(); oracle = _oracle; jobId = _jobId; fee = _fee; } function requestAdPerformanceData() public { Chainlink.Request memory req = buildChainlinkRequest(jobId, address(this), this.fulfill.selector); req.add("get", "https://example.com/api/ad_performance"); req.add("path", "performance"); sendChainlinkRequestTo(oracle, req, fee); } function fulfill(bytes32 _requestId, uint256 _performance) public recordChainlinkFulfillment(_requestId) { adPerformance = _performance; emit AdPerformanceUpdated(_performance); } } Ad Serving and Publisher Integration For ad serving, we’ll need a JavaScript SDK or API that publishers can integrate into their websites or apps. This SDK will interact with the smart contracts and IPFS to retrieve and display ad content. Here’s a simplified example of how this might look in JavaScript: // Load Web3 const Web3 = require('web3'); // Connect to Ethereum node const web3 = new Web3('<YOUR_ETHEREUM_NODE_URL>'); // Load the contract ABI and address const contractABI = [...] // Contract ABI goes here const contractAddress = '0x123...'; // Initialize the contract object const contract = new web3.eth.Contract(contractABI, contractAddress); // Fetch ad campaign details const campaignId = 1; // Example campaign ID const campaign = await contract.methods.campaigns(campaignId).call(); // Load ad content from IPFS const ipfs = require('ipfs-http-client'); const ipfsClient = ipfs.create(); const adContent = JSON.parse(await ipfsClient.cat(campaign.ipfsHash)); // Render ad content on the publisher's website or app // (actual rendering logic will depend on the specific platform and ad format) Conclusion In this article, we’ve explored the technical architecture of a decentralized DSP that handles interactive ad campaigns and rewards users with ERC-20 tokens and NFTs. By leveraging blockchain technology, decentralized storage, and oracles, we can build a next-generation ad platform that offers greater transparency, security, and user engagement. While the examples provided are simplified, they should give you a solid foundation to start building your own decentralized DSP. Lead image by on Unsplash Adem AY Also published here.