How to build a NFT Marketplace with verifiable offchain metadata

IFESA
2 min readJan 2, 2022
Ancon NFT Marketplace

There are two features that are the most important besides smart contracts for a NFT marketplace that are easy but gets complex when it is about to scale:

1 - Distribution

2 - Fees and royalties

Distribution

Becase a NFT publisher does not create one rare item per year, they actually have collections, NFT distribution is an art itself. There is the Voucher technique recommended by NFTSchool.dev, we actually had an Ancon Protocol in Cosmos SDK that used this design pattern.

It means that you first batch NFTs with a signature, offchain, and then its vouched when a first sale occurs.

Fees and royalties

Additionally, you might be a bargain collector which resells to others in second hand markets. Where do you keep track of these exchanges besides the origin contract chain, as fees & royalties storage? You could use blockchain, but considering the gas costs, say you want to give a discount on 1 million NFTs, for that you need databases, like Opensea does, but this is not decentralized.

Enter Ancon Protocol

As a publisher, you first register / claim a DID account seamlessly with your wallet. (Kind of ERC-4337 but similar, we’ll support it Q2).

After that you can create verifiable metadata offchain, these can be proved by any smart contracts with support for Rust, Go, Solidity, Javascript or Cadence. Then enabled NFT contract to only mint if a transfer ownership proof matches.

Because the transfer ownership proof is requested offchain with trusted data retrieval gateway, you can apply the same to obtain fees and royalties from DAG stores in a verifiable and decentralized way.

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IFESA

Industrias de Firmas Electrónicas, S.A. (IFESA) es la primera empresa panameña dedicada a tecnologías basadas en algoritmos criptográficos, firmas electrónicas,