Web Dapp Catalog based on Etherum Blockchain tokens

The client asked us to build a website containing a catalog of Dapps, easy to maintain by non-technical people and containing ad space managed using ERC-721 tokens. 

Technically it needed solutions for several sub-problems:

• A staff site for managing the catalog. The client already knew that using a headless CMS may be the way to go. The question was whether it could meet requirements, 

• A way to moderate ads that ensures law-breaking ads are not displayed on site,

• Implementation of an ERC-721 smart contract with a possibility to buy and sell specific tokens, where each token represents a single ad slot on the website. 

An additional challenge was the fact that resources were limited. This was the very first version of the website and delivering a working solution quickly was crucial to the future of the project.

During the solution design phase, it became clear that there were other challenges that needed to be addressed:

• Where to put the border between distribution and centralization when it comes to managing advertisements, 

• Automating moderation of the website contents to the extent we get a scalable solution with regard to the rate at which ad content is changed. 

The final version of the website consists of:

• A Contentful instance for managing the catalog. Contentful was picked as offering the most flexibility and having the most automation tools for initial and any future development. An important part of this decision was what UI Contentful offers to site administrators – it’s the simplest to use for non-technical people and so fulfills one of the most important aims of our project, 

• A website for browsing the catalog, which was delivered as a simple Single-Page-Application, 

• A service for moderating ads and sending notifications to the client when a new ad is posted. As it needed to check new advertisement contents over time and detect changes, its core part was implemented using Monix’s Observables which simplified the code a lot, 

• An ERC-721 Token allows the management of all the data from the displayed ads, especially their contents and transferring ownership. Smart contracts are used for managing ad slots in different places, leaving full control and transparency to the specific token owner and users without needing to run any additional centralized service if other requirements allow for it.

During the development process, our team used the following technologies:

Backend

1. Scala,
2. AWS, 
3. Jenkins, 
4. Contentful, 
5. Cats,
6. Monix,
7. Play.

Frontend

1. React, 
2. TypeScript, 
3. Rx.JS.

The smart contract was delivered and no further modifications were required after the initial deployment. Thanks to publishing a signed code to Etherscan.io, it is very easy to interact with. Users can explore the applications in an open, trusted and decentralized manner. Each piece of advertising real estate is a unique asset linked to an ERC721 token. This enables each space to be obtained separately utilizing Ether. The ad space owner can advertise, sell, move, rent, or even collect these spaces. The ownership for the spaces is stored on the Ethereum blockchain.