The biggest hurdle we faced was figuring out how to reserve collectibles. Our initial idea was to create a simple skill-based game called "Book Cricket" which users would play. On scoring the required number of runs, they would be eligible to buy a CryptoCricketer NFT. We went down a rabbit hole figuring out reservations, expiry, scoring algorithms, price points, and a host of other product related issues.

From a technical standpoint, we were able to solve for a onboarding users using social login and on successful registration, we created a custodial wallet leveraging the Flow Custodial Wallet. We further wrote smart contracts and exposed a REST interface by storing cadence scripts in the database and loading them dynamically. The scripts interacted with the smart contract to create an account, mint NFT, transfer NFT, and fetch all NFTs associated with a collection. We further formatted the metadata returned in a consumable format similar to Alchemy APIs.

We had the most fun expanding on the work done in the Flow Wallet API by automatically polling for transaction completion and notifying the caller via a webhook or pub-sub mechanism. This feature will allow us to know when a transaction status and charge the payment method successfully.

A last minute feature which we rushed to complete was allowing users to create a digital collectible and mint it from within the app with a UX similar to TikTok.