OpenSea and the Seaport Working Group are excited to unveil Seaport 1.6 — the latest generation of the most advanced NFT marketplace protocol in the EVM ecosystem. 

Seaport 1.6 introduces a new capability enabled by the recent Ethereum Dencun upgrade called Seaport hooks 🪝. Similar in spirit to Uniswap v4 hooks, Seaport Hooks allow developers to build applications that greatly expand the utility and liquidity of NFTs.

What are Seaport hooks?

Seaport hooks allow developers to deploy arbitrary contracts that can be statefully invoked by Seaport during the fulfillment of a Seaport order — sort of like “plugins” built on top of Seaport.  The Seaport technical documentation elaborates on more of the specifics here, but, in summary, it means developers can “plug in” an arbitrary piece of code into the middle of any Seaport sale.

What can be built with it?

Seaport is ultimately a protocol for settling sales of onchain items peer-to-peer.  When you can write smart contracts that “react” to those sales, a lot of interesting things become possible — especially if those smart contracts are the NFTs themselves.  

There are products we are building at OpenSea on top of Seaport hooks, and we’re excited to share them soon.  But Seaport is bigger than just OpenSea, and is a public good & hyperstructure meant for the broader community to innovate on.  Here are some cool ideas we think are worth exploring:

A sale can now source its liquidity — either the items bought or the payment provided — from any place onchain, not just the buyer’s & seller’s wallets.  That means that the world of DeFi becomes much more composable with the NFT universe: automated bonding curves for NFTs can be built, and lending protocols can directly buy / sell into Seaport markets. 

Moreover, sales can now directly inform an NFT about a sale while the sale is happening.  That means NFTs can now be programmed to “react” to being sold under certain conditions — for example by changing metadata in reaction to sale volume.

Price oracles — a staple of DeFi that allows some of the most important protocols to run — become much more feasible for NFTs as well, allowing time-weighted average price (TWAP) oracles.

But the coolest application is almost certainly something we haven’t thought of yet — if you’re building something interesting on Seaport Hooks and think it would integrate well into a product like OpenSea, send us an email at hooks@opensea.io.

Why now?

We’ve been excited about Seaport Hooks for a while, but some of the most interesting applications for Seaport 1.6 only became cost-efficient with the recent introduction of the TSTORE opcode (EIP1153) in the Dencun upgrade.  We, like our colleagues at protocols like Uniswap, have been eagerly awaiting the Dencun upgrade as a critical unlock not only for broader Ethereum scalability (EIP4844) but also for the richer application design space afforded by EIP1153.

When does it go live?

Seaport 1.6 is live and deployed at the addresses listed here today.  OpenSea will begin migrating its users to submit orders on Seaport 1.6 on Monday, March 25th.  The OpenSea API will stop accepting Seaport 1.5 orders on Monday, April 1st. 

The first OpenSea feature to leverage hooks will go live in April.  Stay tuned for more updates.

Why does this matter?

We think NFTs are more than just digital property to be collected, bought, and sold — they are an incredibly rich canvas for building apps and experiences that were never possible in the legacy Internet.  Some of those innovations will be built by OpenSea, but, most will be built by the broader community in form factors we’ve yet to imagine.  

One of our core company values is to “build an ocean, not an aquarium” — “hooks” and the broader Seaport ecosystem are an invitation to the developer and creator community to push the envelope for what’s possible for NFTs, and, ideally, to enable those experiences to be natively surfaced in the most trusted marketplace & homepage for NFTs.

What do I (as a user, or as a developer) need to do?

As a user of OpenSea, you don’t need to worry about anything — Seaport 1.6 orders look and feel largely the same to 1.5 orders, and OpenSea will begin routing listings and offers to Seaport 1.6 automatically on Monday, March 25th.

If you are a user of the OpenSea Developer API, you can begin submitting Seaport 1.6 orders on Monday, March 25th alongside non-programmatic users.  Seaport 1.5 orders will continue to be accepted by the API until Monday, April 1st, at which point they will no longer be accepted as valid.

We will be pushing out updates to both the OpenSea.js and Seaport.js packages on Monday, March 25th that should seamlessly begin signing and submitting 1.6 orders through the same exposed function interfaces as prior — we recommend developers pull the latest versions for either / both packages next week. 

If you are a smart contract developer or a marketplace built on top of Seaport, we recommend studying the new Seaport Developer Documentation, in particular the section pertaining to Seaport Hooks.  Seaport 1.5 remains an unowned hyperstructure that can be built and relied on so long as the Ethereum blockchain runs, but the OpenSea Conduit will be deprecating Seaport 1.5 as an approved channel in the coming months.

Lastly, if you are a developer looking to build a novel application on Seaport Hooks, we again encourage you to reach out to hooks@opensea.io — in particular if you think your Hook would make for a novel feature in OpenSea itself.