LemonAds

Lemonads is a decentralized advertising platform designed to give both publishers and advertisers full control, transparency, and efficiency in the Web3 space. By leveraging blockchain tech, we’ve created a system where publishers can manage ad spaces—called “ad parcels”—on their websites via smart contracts on Ethereum.

Core Features:

Ad Parcel Management

Publishers can set up ad parcels on their websites, each with a unique ID and customizable traits like size, fonts, and placement. This data is stored on IPFS, ensuring decentralization and transparency. They can then rent out these ad parcels to advertisers using automated smart contracts.

Advertiser Flexibility

Advertisers (a.k.a. renters) can place bids on available ad parcels, competing to outbid others for prime ad spots. Once they’ve placed the highest bid, they can upload their ad content—images, links, descriptions—directly to IPFS, ensuring transparency and security. To maintain content quality, all ad uploads go through moderation to prevent inappropriate images. This decentralized approach makes the entire process auditable and ensures the integrity of the ads displayed.

Bidding System

The platform features live bidding, where advertisers compete to place ads in prime spots. Payments are locked into smart contracts, ensuring a smooth transaction flow. If an advertiser’s budget runs out, the parcel is automatically released, and the publisher gets notified.

Automated Payments & Tracking

Leveraging Chainlink and Ethereum smart contracts, the platform automates payments based on ad performance metrics like clicks and interactions. Conversions—actions taken after clicking an ad—are tracked via unique query parameters, and notifications are sent when budgets get low, so advertisers can top up on time.

Conversion Tracking

Advertisers can track conversions (purchases, signups, etc.) through a unique click ID that’s passed when users interact with ads. This allows for a high level of transparency and measurable results for every ad campaign.

Full Transparency

Every transaction—from ad creation, bidding, to payments—is handled by Ethereum smart contracts. There’s no middleman, reducing fraud and ensuring both publishers and advertisers know exactly where their funds are going.

Easy Website Integration

Publishers can quickly embed ad parcels on their site with a simple copy-paste code snippet. This ensures the ad space is live and showing the most up-to-date content seamlessly.

Use Cases:

For Publishers: Monetize website traffic without the hassle. Publishers can manage their ad parcels, set bids, and adjust parcel details while having full transparency.

For Advertisers: Gain full control over where your ads appear, track performance in real-time, and automate payments. If a campaign is successful, the platform automatically handles everything from clicks to conversions, with detailed reporting.

This project is built with a mix of Web3 technologies and traditional web development tools. The smart contracts are written in Solidity using Foundry and deployed on Base Sepolia testnet, handling the bidding, ad parcel management, and payouts in a decentralized manner. We used Chainlink Functions for automated off-chain data aggregation, enabling features like click tracking and automated notifications for renters running low on budget.

On the front end, it’s a Next.js app with React for the UI, utilizing TypeScript for type safety. Ad content is stored on IPFS using Pinata. Content moderation is powered by AWS Rekognition, automatically flagging and blocking inappropriate images before they’re uploaded. The platform also integrates Firebase for user authentication and storing additional metadata.

The UI features a dynamic ad parcel data table with interactive tools for publishers and advertisers, including budget management and embed codes for easy integration into websites. For payments, we use a combination of ETH and smart contract-based budget tracking to ensure transparency between publishers and renters.

One notable hack is our use of Chainlink to trigger off-chain email notifications to advertisers when their funds are low, which uses a combination of our main smart contract, Chainlink functions and an API endpoint that uses nodemailer with uuids to 'reduce' the DON calls to one single email sent per notification required.