What is a Flash Loan?

The meaning of flash loan refers to a type of cryptocurrency loan that requires no collateral, enables near-instantaneous borrowing and repayment, and has a limited duration. It is typically used for short-term operations such as arbitrage trading, liquidity provision, and other speculative strategies. As the transaction occurs in one single Ethereum block, it offers borrowers access to significant amounts of funds. However, the time limitation of the flash loan means that any profits gained from the borrowed amount must be paid back within the same transaction or else the entire loan will be canceled. Therefore, flash loans carry an increased element of risk when compared to more traditional forms of finance. Despite this risk however, they remain popular due to their speed and convenience.

Flash loans can also be used to facilitate more complex strategies such as “loan-on-loan” and “loan-on-chain”, allowing for a greater degree of flexibility. The growing popularity of flash loans indicates that their use is likely to increase in the future. As such, it is important to thoroughly understand the risks associated with this type of loan before engaging in any transactions. Properly managed, flash loans can offer a valuable financial tool for those looking to take advantage of rapid-fire opportunities in the cryptocurrency market.

In summary, a flash loan is an instant and collateral-free loan that can be used for quick financial transactions. It provides borrowers with access to large amounts of capital without the need for collateral, but carries an increased risk due to its limited duration. While this type of loan can offer great potential when employed correctly, it is important to understand the risks associated with them before engaging in any transactions. Proper management of flash loans can provide a valuable financial tool for those looking to take advantage of rapid-fire opportunities in the cryptocurrency market.

Simplified Example

A flash loan is like borrowing a toy from a friend for a short period of time. Imagine you are playing with a toy at a friend's house, but you have to leave soon. Your friend lets you borrow the toy for a short time, like a few minutes, so you can play with it before you have to leave. Similarly, a flash loan is a type of loan that is borrowed and returned within a very short period of time, usually within a few minutes. This type of loan is typically used in decentralized finance (DeFi) and it allows borrowers to borrow assets without a collateral, but they must pay it back within a specific time-frame, otherwise, they may face penalties. It's like borrowing a toy from a friend for a short period of time, you use it and then you return it.

Who Invented the Flash Loan?

Max Wolff is a prominent figure in the decentralized finance (DeFi) space, widely recognized for his contributions to the development and popularization of flash loans. As the co-founder of Marble, a DeFi protocol that pioneered the use of flash loans in 2018, Wolff played a pivotal role in introducing this innovative financial instrument to the world.

Prior to his involvement with Marble, Wolff had a background in computer science and software development, with a particular interest in blockchain technology and its potential applications. His expertise in these areas proved instrumental in the conceptualization and implementation of flash loans. Wolff recognized the immense potential of flash loans as a versatile tool for various DeFi applications, such as arbitrage, collateral swaps, and liquidations. Under his leadership, Marble became one of the first platforms to offer flash loan capabilities, opening up a world of possibilities for DeFi developers.


Ethereum-backed Dharma protocol: Allows users to take out a loan without needing to provide collateral and pay back the same amount within 24 hours.

The dYdX platform: Allows users to use their crypto assets as collateral against their loan instead of fiat currency, making it easier for borrowers who need funds quickly and are unable to access traditional bank loans. An example of a flash loan on dYdX would involve taking out an ETH or DAI backed tokenized loan with terms ranging from 1–15 minutes.

The Aave protocol: A platform that facilitates flash loans, allowing users to take out a loan of up to $1 million using their crypto assets as collateral. An example of a flash loan on Aave would be taking out an ETH or DAI backed tokenized loan with terms ranging from 1–15 minutes and paying back the same amount plus interest within 24 hours. In addition, Aave also has a “flash swap” feature which allows for instant swapping between different tokens without needing to move any funds in and out of the platform. This can be useful for traders who need to adjust their positions quickly in order to take advantage of market opportunities.

  • Flash Loan Attack: A Flash Loan Attack is an attack method used by malicious actors to exploit a decentralized finance (DeFi) protocol.

  • Decentralized finance (DeFi): Decentralized finance (DeFi) refers to a new financial system that operates on blockchain technology, allowing for peer-to-peer transactions without the need for intermediaries such as banks or other financial institutions.