Decentralized Local Marketplace

Incentive the community to filter out illegal trades

Sellers and buyers' history stored on the blockchain

Ability to prove payment occured

Backend/Frontend development

Solidity smart contract development

This decentralized marketplace should have a way to remove illegal trades, a way to verify the credibility of a seller or a buyer and a way to be able to cancel a trade if the item is not as expected.

Here are ways I propose to implement those three functionalities.

How to filter out illegal trades?

Every transaction made on this marketplace would have fees that will be used to incentivise people to report illegal activity. People will be able to report sellers, if enough participants report them, the system will remove the seller from the network and will distribute rewards to the people that reported it.

How to verify credibility of a seller or buyer?

Because every trade someone makes are stored on the blockchain, it is possible to verify the past trade history of them. The system can give "credibility token" to good sellers and buyers. If they act maliciously, their stack of credibility token can be slashed.

How to make sure the item is received?

Before a transaction, the buyer and the seller stake double the cost of the item in a smart contract. When the item is received and the buyer is satisfied, each party gets their stake back and the seller gets their money. This doesn't make sure that the seller really has the item or that the item is as the buyer thought I would be, but it incentivises them to find a solution together and maybe cancel the trade.