Marlowe

A special purpose language designed to allow anyone to write and execute P2P financial contracts on any blockchain.

About Marlowe

Marlowe is:

A domain specific language for finance
Designed for people who are experts in the field of contracts or business, but do not have the programing skills and experience to code smart contracts
A small language with a handful of different constructs that, for each contract, describe behaviour involving a finite set of roles
A peer-to-peer language that users can use to create self executing smart contracts that do not rely on a centralized entity
Embedded in both Javascript and Haskell, offering a choice of editors depending on the user’s skillset
Blockchain agnostic and can be used with both eUTXO and account-based blockchains
Designed as an industry scale solution and embodies example from the ACTUS taxonomy and standard for financial contracts

Marlowe can:

Be built using a visual editor without ever viewing the underlying code
Not wait indefinitely for an action to take place i.e. eventually the contract will timeout and take remedial action, such as refunding any funds
Interact with oracles i.e. utilize off-chain data

Roles in the Marlowe contracts are represented by a token on-chain and this means that roles can be transferred or traded during contract execution

Marlowe Run

Marlowe Run is a client application for Marlowe contracts running on Cardano. Marlowe Run runs in your browser as a distributed application and makes use of the Plutus Application Backend in its execution.

In Marlowe Run users will be able to run their own, self created contract (from in Marlowe Build) or pre-created contracts found on the Marlowe Marketplace.

There are smart contracts templates ready for use on the testnet. Currently available are contracts are called:

Loan
Purchase
Contract for Differences (a bet on outcomes)

Marlowe Build

Marlowe Build is a sandbox environment where users can simulate, build, and develop Marlowe contracts step-by-step, using a visual builder without writing or seeing a single line of code.

This playground allows the user to formally verify and test a smart contract for warnings and errors without running the contract at all.

There are 3 options for writing smart contracts in Marlowe Build:

Write directly in Marlowe text
Use the visual Blockly programing tool to create contract
Use the embedded Haskell or Javascript editor to describe contracts

Marlowe Market

The Marlowe market is yet to be released but once Marlowe is released to the mainnet the Market will function as a smart contract template library, allowing users to come and pick an already built and tested smart contract that fulfills their needs.

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DeFi

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Glossary

Plutus

Plutus is the smart contract platform and language of Cardano and is written in the functional programming language of Haskell. The Plutus platform is used to write and release smart contracts to the Cardano blockchain.

There are multiple tools for learning how to use Plutus to create smart contracts on Cardano. Some of them are official and released by IOHK but many have been made and open sourced by community members.

Oracle

In the ancient world oracles were people through whom the Gods spoke directly to the inhabitants of earth. In the blockchain and crypto world oracles are a service that provides off-chain data to smart contracts running on a blockchain.

On-chain functions, i.e. smart contracts, cannot access real world data on their own. This is problematic when a smart contract is trying to provide the real-time price of financial assets to users, or when it needs to determine the outcome of a sporting event for a gambling protocol, or even when it has been asked to use something measurable in the real world, such as the temperature or quantity of snowfall, in its calculations. Oracles can feed any real world data onto the blockchain for use by smart contracts.

Data is collect it in a variety of ways: APIs, websites, sensors, etc, and can be manual input by humans. This data is collect by nodes and is then passed on to the oracle service that then supplies the smart contract with the data. Having one node supplying data means a central point of failure, and a high potential for manipulation of the data. As a result oracle services usually use a network of nodes to build a consensus of the correct data point and to prevent the data from being manipulated, thereby helping to ensure trust in the data they supply.

On-Chain

These are all the on-chain NFTs, and on-chain NFT collections, that currently exist on Cardano. Many people consider on-chain NFTs to be better, or more special, than off-chain NFTs.

In regards to the on-chain vs off-chain NFT argument, the image represented by an off-chain NFT is found by following a link, typically stored on the IPFS, from the NFTs metadata. This can be changed by the person who uploaded it. The image represented by an on-chain NFT is coded into the metadata and is, therefore, immutably coded into the blockchain's history. This is usually, but not always, in the form a language that your browser understands, allowing your browser to interpret that information and display the NFT.

Loan

Blockchain brings forth a new decentralized method of lending, allowing individuals to offer each other loans in a peer-to-peer fashion through smart contracts. Cardano loan platforms allow you to access Cardano collateral loans, where you lock up your holdings on the Cardano blockchain to receive a loan of equal or lesser value.

These protocols also include unique, Cardano NFT loans, where you can lock your Cardano NFT up in a smart contract, using it as collateral, in return for a loan in ada. All of this is done in a trustless manner through the use of smart contracts on the Cardano blockchain.

On the multiple Cardano loan platforms listed here you can be either the loaner or the loanee, allowing you to access loans using your existing assets as collateral, or to put your ada to work to earn you money by lending it out to others.

Cardano NFT loans are some of the most popular types of loans as the protocols allowing you to complete Cardano NFT loans, Lending Pond and Fluid Token, allow NFT owners to unlock the liquidity locked up in their assets without losing their beloved NFTs (so long as they return the borrowed assets, plus interest, in the allotted time)