Ignis is an essential part of the Ardor platform. It is the main child chain - fully featured and permissionless for everyday transactions with low fees. All the Ardor platform transaction types and features are available on the Ignis child chain. Furthermore, account specific functions, such as setting account properties and multi-signature configurations (account control), are facilitated exclusively by Ignis but accessible across all child chains. Ignis supports out of the box advanced privacy mechanisms including coin shuffling, and encrypted messages which can be shared securely with third parties. Use Ignis to experiment and build public applications with all the features available on the Ardor platform. You don't need any permission, simply install the software, download the blockchain, get some tokens from an exchange (or exchange with ARDR tokens on chain) then start using the APIs and coding. It is really that simple. Ignis is the exclusive chain for stateless lightweight contract development. Use Ignis to deploy your contracts even if they will eventually interact with other child chains.