Badges is an NFT protocol that allows anyone to permissionlessly create digital badges, as rewards for participants of events, or people who achieve certain accomplishments.
The Badges project consists of two smart contracts:
badge-hubis where users create, edit, or mint new badgesbadge-nftis the non-fungible token that implements the SG-721 interface, compatible with the Stargaze marketplace
Creation of new badges is permissionless. When creating a new badge, a fee is charged based on the amount of storage space it consumes. The fee rate, defined as ustars per byte, can be set by L1 governance.
Each badge defines its own minting rule. There are three such rules to be chosen from:
by_minterThere is a designated minter, which can either be a human, a multisig, or another contract implementing custom minting logics. The minter can mint any amount of the badge to any user.by_keyWhen creating the badge, the creator generates a private-public key pair, and provides the contract with the pubkey. The creator should then distribute the privkey off-chain. Any person who receives the privkey can mint an instance of the badge by submitting the signature of a specified message signed by the privkey. The privkey can be used many times, whereas each user can only mint once.by_keysSimilar to the previous rule, but there are multiple privkeys, each can only be used once. Similarly, each user can only mint once.
Each badge can also optionally have a minting deadline and a max supply.
Badges are each identified by an integer number. The first badge ever to be created gets id #1, the second #2, and so on.
Each badge can be minted multiple times; the resulting instances of the badge are each identified by a serial number. For a given badge, the first instance to ever be minted gets serial #1, the second #2, and so on.
That is, each non-fungible token is identified by two numbers, the badge id and the serial number. The CW-721 token_id is defined by joining the two with a pipe character: {id}|{serial}. For example, the 420th instance of badge #69 has a token_id of 69|420.
The metadata of badges are stored on-chain. However, the approach used by cw721-metadata-onchain is not suitable for our use case. The said contract stores a separate copy of the metadata for each token_id. As instances of the same badge all have the same metadata, this is a huge waste of on-chain space.
Instead, only a single copy of the metadata is stored at the Hub contract. When a user queries the nft_info method on the NFT contract by providing a token_id, the NFT contract in turn queries the Hub contract for the metadata, and returns it to the user. In this way, we significantly reduce the contract's storage footprint.
The Hub contract implements two methods, purge_keys and purge_owners, which allows anyone to delete certain contract data once they are no longer needed. This reduces the blockchain's state size and the burden for node operators.
| Contract | Address |
|---|---|
| Badge Hub | stars13unm9tgtwq683wplupjlgw39nghm7xva7tmu7m29tmpxxnkhpkcq4gf3p4 |
| Badge NFT | stars1z5qcmx9frn2y92cjy3k62gzylkezkphdwrx3675mvug3fd9l26fshdd85t |
| Contract | Address |
|---|---|
| Badge Hub | stars1dacun0xn7z73qzdcmq27q3xn6xuprg8e2ugj364784al2v27tklqynhuqa |
| Badge NFT | stars1vlw4y54dyzt3zg7phj8yey9fg4zj49czknssngwmgrnwymyktztstalg7t |
Contents of this repository are open source under GNU General Public License v3 or later.