Obra — Generative NFT Marketplace
Mint, list, collect — all in CHU.
A 100-piece generative NFT collection on BNB Chain, minted and traded entirely in CHU — the ERC-20 token from Level 02. Obra (the ERC-721) and ObraMarket, a fixed-price marketplace with on-chain royalties, share one contract-only architecture: no backend, no database, no private key in the repo. Art and metadata are pinned to IPFS via Pinata.
The problem
Level 03 closes the loop the first two levels set up: proving that a token earned by staking can actually be spent — not just held, and not just spent once. Obra answers whether an ERC-20 can stand in as both a mint currency and a marketplace currency, entirely through contracts, without a backend or a private key ever leaving a browser wallet.
Built with
What went into this
- Minting and buying both spend CHU, the ERC-20 token from Level 02 — the shared on-chain economy, extended into a second use case
- A fixed-price marketplace (ObraMarket) alongside the mint: 2% protocol fee, 5% creator royalty via ERC-2981
- No backend anywhere — the contracts are the entire source of truth, art and metadata pinned to IPFS via Pinata
- 100 generative pieces, capped at 3 per wallet, deployed and configured entirely through a browser wallet — no private key ever touched the repo
- 40 passing Hardhat tests back the Solidity contracts (OpenZeppelin v5)
How it fits together
Obra is two contracts working together: an ERC-721 that mints 100 generative pieces for CHU, and ObraMarket, a fixed-price marketplace that also settles in CHU, charging a 2% protocol fee on top of a 5% creator royalty paid automatically via ERC-2981. Neither has a backend — the contracts are the entire source of truth, art and metadata live permanently on IPFS via Pinata, and every step from mint to list to buy reuses the approve-then-spend pattern CHU already established in Level 02.