Mainframe, now known as Hifi, is a Lending Protocol in the cryptocurrency realm that aims to facilitate borrowing against crypto assets. The protocol employs a bond-like instrument, which signifies an on-chain obligation due on a specific future date. This mechanism aims to enable fixed-rate, fixed-term lending and borrowing, a feature that is increasingly sought after in the decentralized finance (DeFi) landscape. The Mainframe Token (MFT) serves as the native utility token of the protocol, used for governance votes, staking to bolster the protocol's safety, and rewarding contributors to the ecosystem.

Mainframe, or Hifi, operates by allowing users to lock collateral in a vault to mint fixed-rate, fixed-term debt tokens. These debt tokens can be swapped for instant liquidity, enabling users to leverage long, yield farm, or engage in other strategic trades without having to sell their collateral tokens. Users can also buy fixed-rate, fixed-term debt tokens at a discount. Upon the expiry of the term, these tokens can be redeemed for face value, providing lenders with a predictable return on their contribution. Additionally, users can receive compensation from trading fees by providing liquidity between debt tokens and stablecoins on an Automated Market Maker (AMM).

The Mainframe protocol, now known as Hifi, offers a range of potential use cases in the DeFi space. It aims to provide a platform for users to borrow against their crypto assets, offering a way to leverage their holdings without selling. This can be particularly useful for long-term investors, yield farmers, or those looking to engage in strategic trades. Additionally, the protocol allows users to lend by buying fixed-rate, fixed-term debt tokens, offering a predictable return on their contribution. Lastly, the protocol seeks to offer opportunities for users to receive compensation from trading fees by providing liquidity in the AMM.

Mainframe, now rebranded as Hifi, was established by Mick Hagen in 2017. Initially, the team launched a decentralized chat application and a decentralized operating system in 2018 and 2019, respectively. However, these products did not gain significant traction. In 2019, the team pivoted to DeFi and began developing a decentralized lending and borrowing platform. In early 2020, Doug Leonard, who had been with the company since 2018, took over as CEO from Mick Hagen. The team was rebuilt under Doug's leadership, acquiring the token streaming protocol Sablier and hiring its founder and developer, Paul Razvan Berg, as the lead engineer. Mainframe rebranded to Hifi in February 2021.