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Marketplace

·Medialane DAO

Marketplace

The Medialane marketplace runs on two audited Cairo smart contracts on Starknet Mainnet — one for ERC-721 (unique assets) and one for ERC-1155 (multi-edition assets). All orders are SNIP-12 typed-data signed off-chain and fulfilled atomically on-chain.

Order Model

Every marketplace action creates or fulfills an order — a typed-data structure signed by the creator's wallet and registered on the marketplace contract. Key properties:

| Field | Description | |-------|-------------| | orderHash | Unique identifier derived from the signed parameters | | offerer | Address that signed the order (seller for listings, buyer for offers) | | offer | The asset being offered (NFT token for listings; ERC-20 for bids) | | consideration | What the offerer receives in return | | startTime / endTime | Validity window (Unix timestamps) | | salt | Replay-prevention nonce | | status | ACTIVE | FILLED | CANCELLED | COUNTER_OFFERED |

Supported Currencies

USDC · USDT · ETH · STRK · WBTC

All ERC-20 payments are transferred atomically with the NFT transfer inside a single Starknet multicall.

Listings (Fixed-Price Sales)

Creating a Listing

  1. Approve the marketplace contract to transfer your NFT
  2. Sign SNIP-12 typed data (OrderParameters) with your wallet
  3. The dapp submits register_order via a multicall: approve + register_order

Gas is sponsored for ERC-721 and ERC-1155 listings via the AVNU paymaster.

ERC-1155 specifics: You can list a quantity (e.g. sell 5 of your 100 edition copies at once). The offer.startAmount and offer.endAmount specify the quantity.

Duration options

1 day · 3 days · 7 days · 14 days · 30 days

Cancelling a Listing

Sign a CancellationParameters typed-data message and submit cancel_order. The signature proves only the order creator can cancel.

Offers (Bids)

Any wallet can make an offer on any indexed NFT — even assets not currently listed.

Making an Offer

  1. Approve the marketplace contract to transfer your ERC-20 payment token
  2. Sign OrderParameters typed data with the ERC-20 as the offer item and the NFT as consideration
  3. Dapp submits approve + register_order multicall

Accepting an Offer

As the NFT owner (seller):

  1. Review the incoming bid in your Portfolio → Received Offers
  2. Click Accept — signs a FulfillmentParameters typed-data message
  3. Dapp submits approve (ERC-721/1155) + fulfill_order multicall

Royalties are enforced by the contract at fulfillment time.

Counter-offers

Sellers can respond to a bid with a counter-offer — a new order at a different price. The original bid enters COUNTER_OFFERED status. The buyer sees the counter in Portfolio → Counter-offers and can accept or ignore it.

Cart Checkout (Batch Buying)

The cart allows purchasing multiple listings in a single atomic transaction:

  1. Add items to cart (any combination of ERC-721 and ERC-1155)
  2. Cart groups items by payment currency and computes approval amounts
  3. One multicall: approve(totalPerCurrency) × N currencies + fulfill_order × N items
  4. Session-key wallets (Cartridge Controller) sign the full batch once with a PIN

If any fulfillment fails, the entire multicall reverts — no partial purchases.

Smart Contracts

| Contract | Address | Standard | |----------|---------|---------| | Marketplace v2 (ERC-721) | 0x00f8ccaae0bc811c79605974cc1dab769b9cea8877f033f8e3c17f30457caba6 | ERC-721 | | Marketplace v2 (ERC-1155) | 0x02bfa521c25461a09d735889b469418608d7d92f8b26e3d37ef174a4c2e22f99 | ERC-1155 |

Both contracts are non-upgradeable by design and have passed professional security audits.

SNIP-12 Typed Data Domains

Typed data is signed against a specific domain to prevent cross-contract replay attacks.

| Contract | Domain name | Domain version | |----------|-------------|----------------| | ERC-721 marketplace | Medialane | 1 | | ERC-1155 marketplace | Medialane | 2 |

Fee Structure

| Event | Fee | |-------|-----| | List / make offer | Free | | Sale completed | 1% of transaction value → DAO treasury | | Royalties | Set by creator (enforced by contract) |

Portfolio Views

| Tab | Shows | |-----|-------| | Listings | Your active fixed-price listings | | Offers made | Bids you've placed on other assets | | Received offers | Incoming bids on your assets | | Counter-offers | Seller responses to your bids awaiting your decision |

Security Properties

  • CEI pattern — checks, effects, interactions ordering prevents reentrancy
  • Front-running protection — order hash includes price and asset; partial fills are impossible for fixed-price orders
  • Non-custodial — assets stay in creator's wallet until the moment of sale
  • Atomic — payment and NFT transfer happen in the same transaction; neither can succeed without the other