# NFT listings and offers: how signatures become marketplace trades An NFT listing or offer can be a signed order that becomes executable later when its conditions, balances and approvals are satisfied. In Seaport, the order specifies offered items, required consideration, recipients and validity times. Signing it is different from granting token approval, but both can combine to enable a sale without another signature from the seller. Evidence: [Seaport order and fulfillment documentation](https://raw.githubusercontent.com/ProjectOpenSea/seaport/main/docs/SeaportDocumentation.md) Canonical: https://degreesofsatoshi.com/encyclopedia/nft-listings-and-offers/ Published: 2026-10-02 Substantively modified: 2026-10-02 Independently verified by an automated reviewer: 2026-10-02T19:27:58.939Z Data current through: 2026-10-02 AI-assisted research and drafting with a separate automated source-verification pass; no external expert or named human review is implied. ## Key facts - **Offer:** A Seaport order identifies items the offerer will supply. ([Seaport order and fulfillment documentation](https://raw.githubusercontent.com/ProjectOpenSea/seaport/main/docs/SeaportDocumentation.md)) - **Consideration:** It also identifies required items and their recipients. ([Seaport order and fulfillment documentation](https://raw.githubusercontent.com/ProjectOpenSea/seaport/main/docs/SeaportDocumentation.md)) - **Fulfillment:** Valid signatures, time bounds, balances and approvals affect executability. ([Seaport order and fulfillment documentation](https://raw.githubusercontent.com/ProjectOpenSea/seaport/main/docs/SeaportDocumentation.md)) ## An order and an approval do different work A token approval allows the relevant contract or conduit to move tokens. The order specifies the exchange that Seaport may perform using those permissions. Signing a sale message therefore can be materially different from signing a simple login. Read the asset, token ID or criteria, currency, recipients and time window. Some orders cover any eligible token in a set rather than one specific item. Evidence: [Seaport order and fulfillment documentation](https://raw.githubusercontent.com/ProjectOpenSea/seaport/main/docs/SeaportDocumentation.md) ## A signed sale can be filled later Suppose a seller signs an order offering one NFT for 1 ETH before a stated expiry and has granted the necessary transfer approval. A buyer can later fulfill the still-valid order by supplying its required consideration. The seller need not be online to press another approval button. If the seller changes their mind, merely closing the page does not cancel that signed authorization. Seaport documents individual cancellation and counter-based invalidation mechanisms. Evidence: [Seaport order and fulfillment documentation](https://raw.githubusercontent.com/ProjectOpenSea/seaport/main/docs/SeaportDocumentation.md) ## Use the protocol’s cancellation state An offchain website can stop showing an order without making the underlying signed order unexecutable elsewhere. Where cancellation is required, follow the protocol-supported onchain method and verify the resulting state. An expired, cancelled, already filled or insufficiently approved order may fail fulfillment. A listing displayed in an interface is not proof it can still be bought. This example concerns documented Seaport behavior, not every marketplace protocol. Evidence: [Seaport order and fulfillment documentation](https://raw.githubusercontent.com/ProjectOpenSea/seaport/main/docs/SeaportDocumentation.md) ## Questions ### Does signing a listing immediately transfer the NFT? Not necessarily. A signed order can authorize future fulfillment. The actual transfer occurs when an executable order is fulfilled onchain. Evidence: [Seaport order and fulfillment documentation](https://raw.githubusercontent.com/ProjectOpenSea/seaport/main/docs/SeaportDocumentation.md) ### Does removing a listing from a website always cancel its signature? No. Interface removal and protocol cancellation are different. Check the order’s actual cancellation, counter and expiry conditions. Evidence: [Seaport order and fulfillment documentation](https://raw.githubusercontent.com/ProjectOpenSea/seaport/main/docs/SeaportDocumentation.md) ## Claims and scope ### nft-listings-and-offers-quick-answer An NFT listing or offer can be a signed order that becomes executable later when its conditions, balances and approvals are satisfied. In Seaport, the order specifies offered items, required consideration, recipients and validity times. Signing it is different from granting token approval, but both can combine to enable a sale without another signature from the seller. Scope: {"collection":"ethereum","dataAsOf":"2026-10-02","blockHeight":null} ### nft-listings-and-offers-fact-offer Offer: A Seaport order identifies items the offerer will supply. Scope: {"collection":"ethereum","dataAsOf":"2026-10-02","blockHeight":null} ### nft-listings-and-offers-fact-consideration Consideration: It also identifies required items and their recipients. Scope: {"collection":"ethereum","dataAsOf":"2026-10-02","blockHeight":null} ### nft-listings-and-offers-fact-fulfillment Fulfillment: Valid signatures, time bounds, balances and approvals affect executability. Scope: {"collection":"ethereum","dataAsOf":"2026-10-02","blockHeight":null} ## Sources - [Seaport order and fulfillment documentation](https://raw.githubusercontent.com/ProjectOpenSea/seaport/main/docs/SeaportDocumentation.md) — OpenSea contributors. Offer/consideration orders, signed authorization, approval and order fulfillment. Locator: Orders; fulfillment; cancellation; signatures. Retrieved: 2026-10-02T18:58:48.251Z. ## Revision history - 2026-10-02: First publication after primary-source research and separate automated verification. ## Cite this entry Degrees of Satoshi editorial project. “NFT listings and offers: how signatures become marketplace trades.” Published 2026-10-02; updated 2026-10-02. https://degreesofsatoshi.com/encyclopedia/nft-listings-and-offers/