Emoon is a decentralized, peer-to-peer marketplace that uses the 0x protocol to enable trustless buying and selling of crypto assets on top of Ethereum.

If you want to sell an asset, you approve the 0x protocol to broker the transaction with a buyer of your asset. Your asset doesn't leave your possession until someone buys it.

If someone buys your item, Emoon injects your signed order into the 0x smart contracts, which transfers ownership of the asset to the buyer and sends funds from the sale to your account. This transfer of ownership is atomic and is handled by a smart contract on the blockchain.

At any time, you can cancel your listing and take your item off the market, no longer allowing Emoon to sell your asset.

As a buyer, you don't have to worry about a seller's reputation or the seller not delivering your item because the transaction is brokered by the blockchain. All you have to do is pay the Ether asked for by the seller.

Because of how the 0x protocol works, you will get paid in something called wrapped ether (WETH). WETH is identical to ether but it has to be unwrapped. One convenient place you can unwrap your ether is at the 0x portal. Learn more here.
To browse the site, you just need a browser. If you want to make purchases or post listings, you will need a MetaMask, a digital wallet used specifically with web apps. If you are using a mobile device, you can use a mobile browser like Safari or Chrome to browse the site, but if you want list or purchase, you will need to install Trust Wallet, Cipher or Toshi, which are digital wallets like MetaMask but for mobile.
Additionally, if you want to purchase or list, you will need Ether, which is a cryptocurrency that can be used as a form of payment.

Yes! Emoon is a 0x relayer and our entire orderbook is available to be relayed and consumed via an API.

Emoon's API can be found at https://sra.emoon.io. The endpoints of this API are compliant with the 0x SRA API v2. The documentation to the api can be found here. More on the 0x relayer api can be found here.

MetaMask MetaMask is a digital wallet and a tool for interfacing with the blockchain. You will need to add Ether to your wallet to post a listing or purchase a listing.

A mobile dApp browser is a mobile app that acts as both your wallet and your gateway to web3 applications. Similar to how MetaMask turns your desktop browser into a dApp browser, allowing you to sign transactions and interact with the Ethereum blockchain, a dApp browser like Toshi, Cipher Wallet or Trust Wallet acts similarly, storing your private key and signing transactions. It allows you to buy and sell on Emoon.

Trust Wallet is a mobile digital wallet and a dApp browser for interfacing with the blockchain.

Coinbase Wallet is a mobile digital wallet and a dApp browser for interfacing with the blockchain from Android or iOS.

For US citizens, Coinbase is the most established game in town. For non US citizens, there are lots of options on various exchanges.
For your protection, MetaMask will occasionally timeout and lock itself. To unlock it, you just need to click the MetaMask button and unlock it.
Creating a listing is free and there are no charges to the seller. Buying a listing is free and there are no charges to the buyer.
If you don't set an expiry, it default to 30 days. Otherwise, it will expire based on the date you set when creating the listing.
We call into ETH Gas Station to determine the optimal gas price to set. By default, we go with the "safe low" which is explained here. To learn more about the concept of gas and Ethereum in general, see this post.
If you ever see unusually high gas prices, it means that your transaction will likely fail and you shouldn't submit the transaction.