Cool Cats FC Integrates Chainlink VRF to Help Distribute Rewards Fairly

Cool Cats
4 min readDec 16, 2022
Cool Cats FC x Chainlink VRF Integration

We’re excited to announce that Cool Cats FC — an NFT collection created by Cool Cats, Animoca Brands, and OneFootball — has integrated Chainlink Verifiable Random Function (VRF) on Polygon Mainnet. By integrating this industry-leading decentralized oracle network, we have the ability to randomize the distribution of rewards by using a tamper-proof and auditable RNG. Ultimately, this helps produce a more exciting and transparent user experience, as users can verify that they have an equal chance at receiving game-worn and signed merchandise, once-in-a-lifetime IRL experiences, digital collectibles, and much more.

The Cool Cats FC NFT collection is gathering the Cool Cats community and football fans from around the globe to celebrate the world’s biggest sporting event: the World Cup. The Cool Cats FC collection features 3,000 dynamic NFTs, each representing one of the 32 teams taking part. Holders can follow the progress of their team in the tournament and watch their dNFT evolve from the group stage to the round of 16, quarter-finals, semi-finals, and finals.

As their teams advance, holders are eligible to win a range of exciting rewards. The lucky winners of the grand prize will receive a trip to Milan, where they will meet one of the world’s best football players, take a private tour of the San Siro Stadium and the AC Milan museum, enjoy a VIP football match experience at AC Milan, and meet the Cool Cats FC creators. Additionally, all holders have the opportunity to win signed and match-worn jerseys, Italian Serie A match tickets (AC Milan, Juventus, and Napoli)​, and digital collectibles such as Cool Cats NFTs, Cool Pets NFTs, and OneFootball Digital Video Moments (DVM) Packs.

The Benefits of Integrating Chainlink VRF

In order to randomize the distribution of Cool Cats FC rewards, we need access to a secure random number generator (RNG) that any user can independently audit. However, RNG solutions for smart contracts require several security considerations to prevent manipulation and ensure system integrity. For instance, RNG solutions derived from blockchain data like block hashes can be exploited by miners/validators, while off-chain RNG solutions derived from off-chain APIs are opaque and often do not provide users with definitive proof in the integrity of the process.

After reviewing various solutions, Cool Cats FC selected Chainlink VRF because it’s backed by cutting-edge academic research, supported by a reliable time-tested oracle network, and secured through the generation and on-chain verification of cryptographic proofs that verify the integrity of each random number supplied to smart contracts.

“Rewards have become a critical part of launching new NFT collections successfully; giving holders an opportunity to win prizes with real-world utility. By integrating Chainlink VRF into the rewards distribution process for Cool Cats FC, users can verify that they have an equal chance to win signed jerseys, digital collectibles, and a trip to visit the home of AC Milan,” said Stephen Teglas, CEO of Cool Cats.

How Does It Work?

Chainlink VRF works by combining block data, which is still unknown at the time an initial request is made, with the oracle node’s pre-committed private key to generate both a random number and cryptographic proof. The Cool Cats FC smart contract will only accept the random number input if it includes valid cryptographic proof, which can only be generated if the VRF process is tamper-proof. This provides users with automated and verifiable assurances directly on-chain to demonstrate the randomness underpinning our rewards distribution process, proving fair and untampered selection by the oracle, outside entities, or the Cool Cats FC team.

Chainlink VRF process for smart contracts

About Chainlink

Chainlink is the industry-standard Web3 services platform that has enabled trillions of dollars in transaction volume across DeFi, insurance, gaming, NFTs, and other major industries. As the leading decentralized oracle network, Chainlink enables developers to build feature-rich Web3 applications with seamless access to real-world data and off-chain computation across any blockchain and provides global enterprises with a universal gateway to all blockchains.

Learn more about Chainlink by visiting or reading the developer documentation at To discuss an integration, reach out to an expert.

About Cool Cats FC

Cool Cats FC (‘Football Club’) is a collection of 3,000 dynamic NFTs created by Cool Cats, Animoca Brands, and OneFootball Labs. Earn rewards and NFT upgrades for holding the best teams as they advance through the world’s largest football tournament.

Learn more about Cool Cats FC by reading our introduction on Medium and joining us in the Cool Cats Discord. Explore the collection on OpenSea.