Basics

The @polkadot/api-contract comes with 4 general helpers and has *Rx-based versions for the users of the ApiRx version of the API. However here we will focus only on the ApiPromise-based version of the helpers, in much the same way as the API documentation. The four main interfaces provided are:

• CodePromise - upload and instantiate a WASM blob
• BlueprintPromise - instantiate a contract from on-chain code
• ContractPromise - interact with on-chain contract instances, making read calls and executing transactions
• Abi - generic registry that contains all the types and all the messages for a given ABI

Now that we have a good overview of what is available and the use of each interface, let's take a brief tour through the prerequisites needed to complete this guide.