How to implement token registration, trading and enforce the use of native token for fees in a DEX built with Substrate?

Question

How can I implement token registration, trading, and fee payment with my native token (GGG) in a decentralized exchange (DEX) built with Substrate?

Specifically, I am looking to:

Allow users to add their own tokens to the DEX and enable trading between different tokens.

Use an off-chain worker to periodically send data to the main network and enforce the use of my native token (GGG) as the primary token in the network.

Provide a way for users to upload their smart contracts to create custom tokens on my network. I want to know if I should use the substrate-node-contract or pallet-contract feature to do this.

Ensure that all transactions in the network, including those in DApps, are conducted using my native token (GGG) as the fee payment.

I would appreciate it if you could provide guidance on how to implement these features using the capabilities of Substrate.

Answer 1

To make the fee payment with your own token follow this step-by-step old response where you will have to add the pallet_asset_tx_paymentfro.

I believe about how to create your own native token has been answered here already.

To have the functionality that allows users to upload WebAssembly smart-contracts in your chain you have to add in your runtime the FRAME pallet Contracts.

substrate-contracts-node is an example of a node that has this pallet in its runtime. Another example you can check is Contracts Rococo which is a parachain node for smart contracts running in Rococo.

In case you want to allow Solidity Smart contracts, is a bit more tricky but there are some pallets developed that allows it too. You can see an example of a node that has this pallet in its runtime checking the frontier-node-template and a tutorial about how to use it in the Substrate docs: Access EVM Accounts.

With the smart contracts feature you can allow users to develop smart contracts and deploy them in your chain implementing a DEX. You can also implement a pallet with the functionality of a DEX that lives in the runtime of your chain.

I share you some resources that I believe can help:

• substrate-dex pallet: This pallet re-implements Uniswap V1 protocol for decentralized exchange of fungible assets.
• Dex demo build by substrate: This is a full node that acts as a decentralized exchange (DEX) build by substrate.
• Pablo: a new-generation decentralized exchange (DEX) that will be the first protocol to launch on Picasso. Check the code of the pallet here and its implementation in Picasso network here.