I'm using the fa2_nft_minimal.py smart contract that has the following entry point for minting:

    def mint_many(self, to_, metadata):
        token_id = sp.compute(self.data.next_token_id)
        self.data.token_metadata[token_id] = sp.record(
            token_id=token_id, token_info=sp.map({"": metadata},{"": metadata}, {"": metadata})
        self.data.ledger[token_id] = to_
        self.data.next_token_id += 1
    enter preformatted text here

How do I update the contract so it can mint several NFTs in only one operation?

1 Answer 1


Use the fa2 library instead of fa2_nft_minimal.py which is more an example than production ready.

Option A: each minted NFT has different metadata

Solution: use the MintNft mixin that accepts batchs. The example is here: https://smartpy.io/docs/guides/FA/FA2/examples/#with-admin-and-mint

import smartpy as sp
FA2 = sp.io.import_script_from_url("https://smartpy.io/templates/fa2_lib.py")

class NftWithAdmin(FA2.Admin, FA2.MintNft, FA2.Fa2Nft):
    def __init__(self, admin, **kwargs):
        FA2.Fa2Nft.__init__(self, **kwargs)
        FA2.Admin.__init__(self, admin)

@sp.add_test(name="NFT with admin and mint")
def test():
    sc = sp.test_scenario()
    c1 = NftWithAdmin(
        admin = sp.test_account("admin").address,
        metadata = sp.utils.metadata_of_url("https://example.com"),
    sc += c1

Option B: All tokens minted in batch share the same metadata

Solution 1: Use fungible tokens. In this case, same answer as Option A except Nft is replaced by Fungible.

Solution 2: create your own mint entrypoint:

    def mint(self, batch):
        """Admin can mint new or existing tokens."""
                    metadata=sp.TMap(sp.TString, sp.TBytes),
                ).layout(("to_", "metadata"))
        sp.verify(self.is_administrator(sp.sender), "FA2_NOT_ADMIN")
        with sp.for_("action", batch) as action:
            with sp.for_("to_", action.to_) as to_:
                token_id = sp.compute(self.data.last_token_id)
                metadata = sp.record(token_id=token_id, token_info=action.metadata)
                self.data.token_metadata[token_id] = metadata
                self.data.ledger[token_id] = to_
                self.data.last_token_id += 1
  • This batch mint it multiple tokens, how would you mint a single token with multiple references? Commented Oct 27, 2022 at 16:46
  • I updated my answer.
    – Jordan_tez
    Commented Oct 29, 2022 at 12:24

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