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Mint Fungible Tokens with On-Chain Data

You, as a developer, maybe also a game fancier, recently starts to develop a game and hope to integrate it with some web3 experience. You spontaneously think Aptos supports fungible tokens with abundant APIs in the token standard. So you wanna give a try to issue an in-game currency called silver coin by using the Aptos command line interface (CLI). There is only two requirements:

  • The token is fungible
  • The token is associated with a URL that points to the coin image.

Create a collection​

Token must belong to a collection. First, you can create a collection by running Aptos CLI:

aptos move run --function-id 0x3::token::create_collection_script --args string:"Game Coins" string:"The collection of all in-game coins" string:"" u64:0 'bool:[false,false,false]'

Parameters:

  • collection name: "Game Coins".
  • collection description: "The collection of all in-game coins".
  • uri: It's empty because we don't intend to have an url for this collection. In general, you could put an image or a JSON url here representing the collection or providing rich metadata.
  • maximum: 0. 0 means there is no maximum limit for the size of the collections.
  • mutability vector:
    1. description: false
    2. uri: false
    3. maximum: false

All the parameters could be adjusted as appropriate.

Create tokens​

The fungible token in Aptos has a unique TokenId, a set of creator, collection name, token name and property version. For fungible tokens, the property version is always 0. To create a token named "Silver Coin", you run:

aptos move run --function-id 0x3::token::create_token_script --args string:"Game Coins" string:"Silver Coin" string:"The currency in my game" u64:100 u64:0 string:$TOKEN_URL address:$YOUR_ADDRESS u64:0 u64:0 'bool:[false,false,false,false,false]' raw:00 raw:00 raw:00

Parameters:

  • collection name: "Game Coins", same as the previous step.
  • token name: "Silver Coin".
  • token description: "The currency in my game".
  • maximum: 0. 0 means there is no maximum supply of this token.
  • uri: Your token url can point to anything. Usually it is an arweave or ipfs url pointing to a token image or JSON file containing the required metadata.
  • royalty_payee_address: Used for NFT. For FT, it is recommended to set the creator address.
  • royalty_points_denominator: Used for NFT. Set to 0 as N/A.
  • royalty_points_numerator: Used for NFT. Set to 0 as N/A
  • token_mutate_config
    1. maximum: false
    2. uri: false
    3. royalty: false
    4. description: false
    5. property map: false
  • property_keys: empty as we don't need any special property.
  • property_values: ditto.
  • property_types: ditto.
Customized Property Map

The last three CLI arguments passed into move run is "raw" type because current CLI doesn't support vector<string> type as pass-in arguments. So for empty vectors, we can easily hack it using the raw serialized format (0x00 is BCS-ed binary format of any empty vector). We are working hard to support it later. Therefore, if you need customized properties to be set, please use our Rust/Typescript/Python SDK instead for now.

After run this command, you, the creator account, will have created your "silver coin" and mint 100 silver coins to your account.

Mint, Transfer and Burn​

After silver coin is created, As the creator, you can mint or burn at your own discretion and anyone who owns silver coin can transfer or burn any amount of tokens not exceeding the balance.

Mint​

To mint 1000 tokens, the creator can run:

aptos move run --function-id 0x3::token::mint_script --args address:$YOUR_ADDRESS string:"Game Coins" string:"Silver Coin" u64:1000

Parameters:

  • creator address: put your creator address here.
  • collection name: "Game Coins", same as before.
  • token name: "Silver Coin", same as before.
  • mint amount: 1000.

Transfer​

To transfer 20 tokens to a receiver, the owner can run:

aptos move run --function-id 0x3::token::transfer_with_opt_in --args address:$CREATOR_ADDRESS string:"Game Coins" string:"Silver Coin" u64:0 address:$RECEIVER_ADDRESS u64:20
Opt-in direct transfer

Aptos token contract, to avoid receiving spam tokens, by default disable direct transfer of any token, which means if the receiver does not opt-in direct transfer of a specific token, the sender calling transfer_with_opt_in will get an error. Thus, if the receiver wish to accept this token, she has to run the following command first.

aptos move run --function-id 0x3::token::opt_in_direct_transfer --args bool:true

Burn​

If you are the creator, you can burn silver coins from any account. If you are an owner, you are only allowed to burn your own silver coins.

To burn 10 tokens as a creator from any owner's account, you can run:

aptos move run --function-id 0x3::token::burn_by_creator --args address:$OWNER_ADDRESS string:"Game Coins" string:"Silver Coin" u64:0 u64:10

Parameters:

  • owner address: put the address of any owner of silver coin here.
  • collection name: "Game Coins", same as before.
  • token name: "Silver Coin", same as before.
  • property version: 0. FT will always have 0 as property version.
  • burn amount: 10.

To burn 10 tokens as an owner, you can run:

aptos move run --function-id 0x3::token::burn --args address:$CREATOR_ADDRESS string:"Game Coins" string:"Silver Coin" u64:0 u64:10

Since owner will burn silver coin from her own address, owner address is not required as a parameter.

Parameters:

  • owner address: put the address of the creator of silver coin here.
  • collection name: "Game Coins", same as before.
  • token name: "Silver Coin", same as before.
  • property version: 0. FT will always have 0 as property version.
  • burn amount: 10.