This unit introduces the ERC20 Messaging dApp, a sample dApp served by Topos. You will invoke a cross-subnet token transfer and observe the process as if from a typical user's perspective.

Topos Explorer is a useful tool to observe the Topos Testnet. Optionally, you can also use it for a locally deployed network.

This unit introduces the Topos Playground, a tool to start a local test network. The Topos Playground incorporates a number of distinct components, each of which are worthwhile examining individually. In this unit, you can find a walkthrough for the installation process, and look at the TCE network, the Topos Subnet, the Incal subnet, and the ERC20 Messaging Frontend in more detail.

Part of the power of Topos is the zkEVM. This unit shows you how to run the topos-zkevm-demo CLI tool in order to experience the power of the zkEVM on your local system.

The Topos CLI is frequently mentioned in this chapter – here you will look at it directly. You will install and test the tool that allows you to collectively start and run the different components you have been exploring.

The Topos public testnet is there for our developer community to deploy apps and experiment with the novel interaction model the Topos protocol enables. It's an early preview of what is coming. In this section we present the upcoming phases to give interested parties and overview of the remaining phases.