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Managing tokens

Tezos supports a variety of types of tokens, including:

  • Fungible tokens, which are collections of interchangeable tokens with a quantity that you define. Fungible tokens can be quantifiable commodities like in-game currency, fuel, ammunition, or energy, or they can be identical items with a limited quantity.
  • Non-fungible tokens (NFTs), which are unique assets with only one unit. Games use NFTs for items that are unique and must not be duplicated.

You can create as many tokens and types of tokens as you need in one contract, but each transaction to create or transfer tokens incurs fees.

For more information about tokens, see Tokens.

FA2 tokens​

While you can create tokens that behave in any way that you want them to behave, it's best to create tokens that follow a standard. The Tezos FA standards enforce a standard format for tokens which allows applications like games, wallets, and block explorers to work with them in a consistent way. For example, if you create an FA-compatible token and use it in a Unity application, players can look up information about their tokens in block explorers and transfer them with their wallets without interacting with the Unity application.

For this reason, Unity applications should use FA tokens whenever possible.

The most popular and commonly-supported FA standard is FA2, so the examples on this page are for working with FA2 tokens. FA2 tokens can be fungible tokens or non-fungible tokens, which makes the standard flexible enough for most uses of tokens.

FA2 token contracts​

To create and work with FA2 tokens you must deploy an FA2-compatible smart contract. For examples of FA2 contracts, see Sample smart contracts. You can also use the tutorial Create a fungible token with the SmartPy FA2 library to walk through the process of creating, customizing, and deploying an FA2 contract.

note

The rest of this page assumes that you are using an FA2 contract.

note

You can use block explorers for help formatting the parameters for contract calls. See Encoding parameters as JSON strings.

Creating (minting) a new token type​

To create a new type of token and mint tokens, pass the metadata for the new token type, the number of tokens to mint, and the initial owner of the new tokens to the FA2 contract's mint entrypoint. The FA2 standard does not require contracts to have a mint entrypoint, but most do. If a contract does not have a mint entrypoint, it was created with all of the tokens that it will ever have and therefore no more tokens can be minted.

TODO

Creating (minting) tokens of an existing type​

To mint tokens of an existing type, pass the token ID, the number of tokens to create, and the initial owner of the new tokens to the contract's mint entrypoint. This example mints 5 tokens of the token type with the ID 7:

var mintJsonString = "{ \"prim\": \"Pair\", \"args\": [ { \"prim\": \"Pair\", \"args\": [ { \"string\": \"tz1QCVQinE8iVj1H2fckqx6oiM85CNJSK9Sx\" }, { \"int\": \"5\" } ] }, { \"prim\": \"Pair\", \"args\": [ [], { \"int\": \"7\" } ] } ] }";

var mintTokensRequest = new OperationRequest
{
   Destination = "KT1Nhr9Bmhy7kcUmezRxbbDybh5buNnrVLTY",
   EntryPoint = "mint",
   Arg = mintJsonString,
   Amount = "0",
};

var response = await TezosAPI.RequestOperation(mintTokensRequest);

Transferring tokens​

To transfer tokens, pass the source account, target account, token ID, and quantity to the contract's transfer entrypoint. The account that sends the transfer call must be the owner or operator of the tokens. For more information about token access control, see FA2 tokens.

This example transfers 2 tokens with the ID 7:

var transferTokensString = "[ { \"prim\": \"Pair\", \"args\": [ { \"string\": \"tz1QCVQinE8iVj1H2fckqx6oiM85CNJSK9Sx\" }, [ { \"prim\": \"Pair\", \"args\": [ { \"string\": \"tz1hQKqRPHmxET8du3fNACGyCG8kZRsXm2zD\" }, { \"prim\": \"Pair\", \"args\": [ { \"int\": \"7\" }, { \"int\": \"2\" } ] } ] } ] ] } ]";

var transferTokensRequest = new OperationRequest
{
    Destination = "KT1Nhr9Bmhy7kcUmezRxbbDybh5buNnrVLTY",
    EntryPoint = "transfer",
    Arg = transferTokensString,
    Amount = "0",
};

var response = await TezosAPI.RequestOperation(transferTokensRequest);

Getting token balances​

You can get information about the tokens in a contract by passing the address of the contract and the maximum number of tokens to return to the TezosAPI.GetTokens() method. The response is a list of TokenData objects with information about the tokens:

var tokenList = await TezosAPI.GetTokens<List<TokenData>>("KT1Nhr9Bmhy7kcUmezRxbbDybh5buNnrVLTY", 20);
foreach (TokenData token in tokenList)
{
    Debug.Log($"Token ID {token.TokenId} has {token.HoldersCount} owners.");
}

Destroying (burning) tokens​

The FA2 standard does not have a standard way of burning tokens. Some FA2 implementations have a burn entrypoint. In other cases, if you want to make tokens unusable, send them to an address that doesn't exist or to an account that you can't use. For example, you can create an account in a wallet app, send the tokens to it, and delete the private key for the account.

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