ERC-721 Token Standard and Smart Contract
Our NFTs are created based on ERC-721 Token Standard (1) and are OpenSea compatible. The open-source contract is written in Solidity and deployed on Polygon Network.
Which network do we mint the NFTs on?
Our NFTs are minted on Polygon Network (formerly known as Matic Network) which is a Layer-2 Solution, in order to keep the transactions speedy and reduce gas fees. Layer-2 Solution is known to be fit for low transaction-fee, non time-sensitive use cases like NFTs, native in-game tokens etc.
Is the data stored off-chain or on-chain?
The metadata of the certificate (Full Name, Course Name, Enrolment ID, Learner ID, Graduation Date and the IPFS link to the NFT image) is stored on-chain. This ensures easy verification of the certificate.
We do not store your certificate image on any centralised server like S3 but we use IPFS (a distributed file-storing system) so that users can always have access to the data. We use Pinata, which offers scalibility and high performance for IPFS storage use-cases. IPFS is also compatible with OpenSea.
To optimise gas fee for minting, we store a copy of the NFT Image off-chain on IPFS, as storing the entire image will be costly (Our certificate images are of high quality). Hence we only encode and store the IPFS hash of the image on-chain.
How can I view my Nas Academy NFTs?
There are three ways you can view your Nas Academy NFTs
Can I view my NFTs in MetaMask?
At the moment, you can ONLY view your NFTs in MetaMask Mobile App UI.
According to MetaMask Support: Please note that while you can add NFTs as custom tokens in the desktop Browser extension, you will not be able to see them natively in the UI.
We are actively working on improving NFT support in MetaMask Extension; it will be available soon, and this information will be updated when it becomes available. For the time being, to manage your NFTs via MetaMask, please use MetaMask Mobile.
Check out the official MetaMask link to see how you can turn on NFT auto-detection (Opensea compatible tokens) or import tokens manually into your wallet: https://metamask.zendesk.com/hc/en-us/articles/360058238591-NFT-tokens-in-your-MetaMask-wallet
Code
Our contract code can be viewed below
(To update with production contract)
Mint and transfer NFT to Nas Academy. Only owner (Nas Academy) can modify attributes if required
Legend
(1) ERC-721 Token Standard for Non-fungible tokens: https://eips.ethereum.org/EIPS/eip-721
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