I was hired as a Blockchain Developer to build a casino roulette game using Solidity smart contracts on the Polygon network. The project leveraged the platform's existing prediction market contracts, which allowed stakers—users with a certain amount of tokens staked—to create betting rooms. Players could enter these rooms and bet their USDT tokens without needing to stake anything beforehand. The winner would be selected using Chainlink RNG (Random Number Generator), ensuring fairness and verifiable randomness.The primary objective was to design a transparent, trustable roulette game where the betting outcomes were determined in a randomized manner using Chainlink's decentralized oracle network. This created a verifiable process that increased user confidence in the platform. Despite the solid technical foundation, the project was discontinued due to low user traction, and the company eventually ceased operations.
Key Features
Casino Roulette Smart Contracts: I developed Solidity smart contracts for a casino roulette game, integrated with the existing prediction market contracts. Stakers (users with staked tokens) could create rooms with fixed outcomes (matching the outcomes of a casino roulette game), and other players could enter the rooms and bet USDT tokens on their chosen outcomes.
Chainlink RNG Integration: The roulette game used Chainlink's Random Number Generator (RNG) to select the winning outcome randomly and verifiably. This ensured that all participants could trust that the game results were fair and transparent.
Polygon Blockchain: The game was built on the Polygon network to take advantage of its low transaction fees and fast processing times, essential for smooth gameplay and quick transactions.
The Graph Protocol for Event Listening and API: To save gas costs and avoid unnecessary on-chain data storage, I used The Graph Protocol to listen to smart contract events. This created a GraphQL API that exposed the data to the frontend, allowing the application to query real-time information, such as bets and outcomes, without needing to store excessive variables on-chain.
Internal React Frontends: Alongside smart contract development, I built internal React frontends to demonstrate the functionality of the contracts. These frontends were crucial for showcasing the progress of my work to the team and testing the integration with the existing systems.
Subgraphs for Event Queries: I implemented subgraphs using The Graph to allow clients to query event data efficiently, such as bets placed, winning outcomes, and transaction details, without overloading the blockchain with unnecessary storage.
Technologies Used
Solidity: Developed the casino roulette smart contracts on Polygon, integrating them with the platform’s existing prediction market contracts.
Chainlink RNG: Integrated Chainlink's Random Number Generator (RNG) to ensure fair and verifiable randomness in the roulette game's outcomes.
Polygon: Deployed the contracts on the Polygon network for its scalability, low gas fees, and fast transaction processing, making it ideal for a casino betting platform.
The Graph Protocol: Used The Graph to set up subgraphs that created a GraphQL API, exposing event data for the frontend to query efficiently. This approach significantly reduced gas costs by avoiding unnecessary on-chain data storage.
React: Built internal React frontends to demonstrate the progress of my work and to test the interaction between the frontend and the smart contracts.
Challenges and Learnings
This project presented a unique challenge as it involved integrating casino game mechanics with blockchain technology, specifically using Chainlink's RNG for randomized outcomes. The task required designing a smart contract system where stakers could create betting rooms, and players could freely join and place bets with USDT tokens. Ensuring the system worked smoothly on the Polygon network while maintaining low gas fees and quick transaction times was a key requirement.Another critical aspect was using The Graph Protocol to track contract events and create a GraphQL API, significantly optimizing gas costs by avoiding unnecessary on-chain data storage. Building subgraphs that allowed querying of real-time betting events was a valuable learning experience, and it helped streamline data retrieval for the users.Developing internal React frontends to showcase the progress of my work was also essential. These frontends allowed for visual demonstration of how the smart contracts operated in real-time, helping the team and stakeholders to understand the system's functionality.
Outcome
Despite the project's technical success and the innovative use of Chainlink RNG and Polygon, it was discontinued due to low user traction. However, the project offered invaluable experience in integrating decentralized randomness, creating efficient casino-style smart contracts, and optimizing data queries through The Graph Protocol and GraphQL API. The company ceased operations shortly after, but the project remains a significant highlight in my blockchain development career.
