Now open: ERC-1155 marketplace

Semi-fungible collectibles are now on OpenSea

Alex Atallah
Sep 11 · 6 min read

Today, OpenSea is announcing a new type of tradable digital assets on the marketplace: ERC-1155 items. In short, these are like ERC-721 items, but they have different behavior and more flexibility, which we’ll explain below. It’s a new Ethereum token standard and a new type of dapp on OpenSea!

There’s some new fish in the sea. Featuring items from Forest Knight, Cats in Mechs, Enjin, Age of Rust, Spirit Clash, and The Six Dragons.

ERC-1155 items have been tradable on OpenSea for a while now (there are over 200,000 that you can find already), but today they get the full attention that they deserve. Let’s start with what’s new in 1155. Then we’ll explain how you can get started trading, which games are already supported (17 so far!), and how developers can make 1155-compliant dapps!

What is ERC-1155 and What’s New

The ERC-1155 token standard provides a way to make one smart contract govern almost an unlimited number of tokens — technically, 2²⁵⁶ token types with up to 2²⁵⁶ copies of each. Additionally, each token is semi-fungible. Unlike ERC-721 non-fungible tokens (NFTs), which can only be owned by one address each, semi-fungible means:

  1. Each token type can be owned by multiple addresses
  2. One address can own multiple copies of each token

This expands the design space for building game economies and provides efficiency benefits as well. ERC-1155 is a result of the combined efforts of multiple companies working together to achieve these two goals, including Enjin, Horizon Games, and The Sandbox.

What’s needed now is a marketplace for the (at the time of writing) 208,319 new semi-fungible assets on Ethereum! And that’s what’s here today:

How to Trade ERC-1155 Tokens on OpenSea

Check out your OpenSea account page to see which items you already own, or visit the supported collections on OpenSea (listed below) to buy one.

To sell an ERC-1155 item, it’s as simple as clicking Sell, and then specifying the total price and quantity you want to sell. If you specify an end date, the price will decline to the amount you want until the end date is reached, and then your listing will be automatically cancelled (expired) for free.

You only have to pay gas the first time do you sell an item (which may include approving the token for trading). If you want to sell for Enjin ENJ, Sandbox SAND, or another payment token, click the dropdown below and set your price:

Selling an ERC-1155 item on OpenSea. Available payment tokens depend on the developer’s preferences.

As with other tokens on OpenSea, you can place offers on 1155 items by clicking “Make an Offer” on the item’s page. Offers are non-binding, but because an item can have multiple owners now and any owner can accept it for you, many people will consider your offer at once!

ERC-1155 Games on OpenSea

Even before this official launch announcement, there are already 17 games on OpenSea using mainnet ERC-1155 contracts, and many are already ranked in the top fifteen dapps by volume. Here’s a full list, with many more to come! Special thanks to all of them for working with us to make a great marketplace experience.

You can also see these games with the “new” label on the OpenSea rankings page, ranked by weekly volume: https://opensea.io/rankings.

Information for Developers

Interested in deploying an ERC-1155 contract on OpenSea? If you already have an 1155 contract on mainnet or the Rinkeby testnet, there’s a chance that OpenSea automatically discovered your items! You can visit them on their owners’ account pages or at opensea.io/assets/TOKEN_ADDRESS/TOKEN_ID, where the TOKEN_ID is the base-ten version of your token id.

You can also use the Get Listed flow to have OpenSea re-crawl the items and add them to the marketplace:

Mainnet: https://opensea.io/get-listed

Rinkeby: https://rinkeby.opensea.io/get-listed

Contact us in the #developers channel on Discord! We’ll help get you set up.

We can help you get started. We’ll edit this page to include our upcoming tutorial, but in the meantime, contact us in the #developers channel on Discord or on Telegram! We’re very responsive :)

What’s Coming Next

Crowdsales, gas-free pre-sales, and whitelisted airdrops using ERC-1155! Stay tuned using any of the following channels, ranked by signal-to-noise ratio ;)

Sam from Spirit Clash in their Telegram

OpenSea

Buy, sell, and discover rare digital items

Thanks to Daniel Viau

Alex Atallah

Written by

Co-founder of @ProjectOpenSea | previously @YCombinator, @PalantirTech, @Apple

OpenSea

OpenSea

Buy, sell, and discover rare digital items

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