Tether (USDT) is a cryptocurrency with a value meant to mirror the value of the U.S. dollar. The idea was to create a stable cryptocurrency that can be used like digital dollars. Coins that serve this purpose of being a stable dollar substitute are called “stable coins.” Tether is the most popular stable coin and even acts as a dollar replacement on many popular exchanges! According to their site, Tether converts cash into digital currency, to anchor or “tether” the value of the coin to the price of national currencies like the US dollar, the Euro, and the Yen. Like other cryptos it uses blockchain. Unlike other cryptos, it is [according to the official Tether site] “100% backed by USD” (USD is held in reserve). The primary use of Tether is that it offers some stability to the otherwise volatile crypto space and offers liquidity to exchanges who can’t deal in dollars and with banks (for example to the sometimes controversial but leading exchange Bitfinex). The digital coins are issued by a company called Tether Limited that is governed by the laws of the British Virgin Islands, according to the legal part of its website. It is incorporated in Hong Kong. It has emerged that Jan Ludovicus van der Velde is the CEO of cryptocurrency exchange Bitfinex, which has been accused of being involved in the price manipulation of bitcoin, as well as tether. Many people trading on exchanges, including Bitfinex, will use tether to buy other cryptocurrencies like bitcoin. Tether Limited argues that using this method to buy virtual currencies allows users to move fiat in and out of an exchange more quickly and cheaply. Also, exchanges typically have rocky relationships with banks, and using Tether is a way to circumvent that. USDT is fairly simple to use. Once on exchanges like Poloniex or Bittrex, it can be used to purchase Bitcoin and other cryptocurrencies. It can be easily transferred from an exchange to any Omni Layer enabled wallet. Tether has no transaction fees, although external wallets and exchanges may charge one. In order to convert USDT to USD and vise versa through the Tether.to Platform, users must pay a small fee. Buying and selling Tether for Bitcoin can be done through a variety of exchanges like the ones mentioned previously or through the Tether.to platform, which also allows the conversion between USD to and from your bank account.
Dai is a stablecoin. It is an Ethereum ERC20 token that is pegged to $1 USD — every Dai is worth $1, and will always be worth $1, regardless of how much Dai is in existence. There is no centralized authority like Tether that backs its value, and no traditional bank that backs each Dai with a real US dollar. There is nothing that can be shut down, and no centralized authority that needs to be trusted. Dai lives entirely within the Ethereum blockchain using smart contracts. *Features of Dai: 1. Dai is always worth $1 USD each 2. It can be freely traded like any other ERC20 token 3. Anyone with an Ethereum wallet can own, accept, and transfer it 4. It can be exchanged without any middleman 5. No individual person or company has control over it 6. No government or authority can shut it down *How Dai Works? Dai is a masterpiece of game theory that carefully balances economic incentives in the pursuit of one goal — a token that is continuously approaching the value of $1 USD. When Dai is worth above $1, mechanisms work to decrease the price. When Dai is worth below $1, mechanisms work to increase the price. The rational actors that take part in these mechanisms do so because they earn money anytime Dai is not perfectly worth $1. This is why Dai is always floating slightly above or below $1 — it is an endless wave function bouncing infinitely close to $1, but never quite achieving it. The farther Dai goes from $1, the more incentive there is to fix it. This is the magic of Dai. *How is Dai Created? Dai is simply a loan against Ethereum. By using the MakerDAO dApp, advanced users can take loans out in Dai against their ETH holdings. First, ETH is turned into “wrapped ETH” (WETH), which is simply an ERC20 wrapping around ETH. This “tokenizes” ETH so it can be used like any other ERC20 token. Next, WETH is turned into “pooled ETH” (PETH), which means it joins a large pool of Ethereum that is the collateral for all Dai created. Once you have PETH, you can create a “collateralized debt position” (CDP), which locks up your PETH and allows you to draw Dai against your collateral, which is PETH. As you draw out Dai, the ratio of debt in the CDP increases. There is a debt limit that sets a maximum amount of Dai you can draw against your CDP. Once you have Dai, you can spend or trade it freely like any other ERC20 token. *There are several important reasons why you would create Dai, despite the hassle: 1. You need a loan, and have an asset (ETH) to use as collateral for your loan 2. You believe ETH is going up in value. You can use your CDP to buy ETH on margin — you lock up your ETH in a CDP, draw Dai against it, use the Dai to buy more ETH on an exchange, and then use that ETH to further increase the size of your CDP. This can be accomplished without any third-party or centralized authority allowing you to do so — margin trading can be accomplished entirely on the blockchain. 3. The demand for Dai has driven the price above $1 USD. When this occurs, you can create Dai then immediately sell it on an exchange for greater than $1 USD. This is essentially free money, and is one of the mechanisms the Maker system uses to keep Dai pegged to $1 USD. Dai being worth over $1 USD encourages more Dai to be created. These three reasons are enough to ensure that Dai is continually created.