CosmWasm is modular, meaning that any blockchain using the Cosmos SDK can add smart
contract support to their chain. That is similar to the Substrate
approach, where chains have the option to add
pallet-contracts to their runtime.
Aside from that, the architecture philosophy is likely the point where CosmWasm and ink! differ the most. CosmWasm follows the actor model design pattern, while ink! follows a synchronous execution model. That means some fundamental differences in how the source code is structured.
The main entry point functions of CosmWasm contracts are:
instantiatewhich bootstraps the initial contract state (assuming it's already been deployed).
executewhich has the actor perform operations to its internal state.
querywhich retrieves data from the actor’s internal state.
An ink! contract can have as many public dispatchables as the developer desires, and differently from CosmWasm, it doesn’t rely on JSON schemas for defining how the messages are structured.
Instead, ink! makes heavy usage of Rust macros. The main ink! macros are:
#[ink(constructor)]which is called when the contract is deployed, and is responsible for bootstrapping the initial contract state into the storage. It is analogous to the CosmWasm
#[ink(storage)]which annotates a struct that represents the contract's internal state.
#[ink(message)]which marks a function as a public dispatchable, meaning that it is exposed in the contract interface to the outside world. This macro can make a function behave analogously to CosmWasm’s
queryfunctions. This depends on how it affects the internal contract state and what the return types.
#[ink(topic)]which annotates a struct and its members as the events and topics that the contract might emit.
There are other ink! macros, for which details can be found at Macros & Attributes.
Unit testing in CosmWasm is quite similar to ink!. Both use the conventional Rust
#[cfg(test)] macro and set up a mock on-chain environment.
While CosmWasm unit tests have different modules for each of the three main entry-point
functions, ink! allows for a more generalised approach, where the
#[ink(test)] macro is
used for each unit test.
You can read more about ink! unit tests here.
Local Development Network
In terms of local development networks, the cosmos/gaia
repository acts as the basic template for a generic Cosmos node. With the addition of the
x/wasm module and some clean-up, this template repository becomes
wasmd, the entry point for CosmWasm development.
In terms of Substrate,
substrate-node-template is a basic generic template of a node.
is the module that adds WebAssembly smart contract functionality to the chain. Parity
provides the substrate-contracts-node,
which is analogous to
wasmd - a basic template node for smart contract development.
For CosmWasm development and on-chain testing,
wasmd can be operated as a local setup
(single or multiple nodes), or connected to the
cliffnet public test network.
ink! contracts can be deployed on a few different options:
- Locally, on a single or multiple node setup of
- Contracts on Rococo Parachain, which is connected to the Rococo relay chain test network.
- Astar Network’s Shibuya testnet.
The first step in CosmWasm development is to
namely Go, Rust and
For ink! you can also find a setup guide which will help you
with dependencies, namely Rust,
The next step in the CosmWasm development workflow is
setting up the environment.
That consists mainly of configuring
wasmd such that it has prefunded accounts that are able
to interact with the network.
substrate-contracts-node is started with the
--dev flag, it already contains well
known pre-funded accounts (
bob, etc.) which are ready to be used for development.
Compile and Test
CosmWasm provides example contracts at the cw-contracts repository. After the repository is cloned, from the contract directory it can be compiled via:
$ cargo wasm
and tested via:
$ cargo unit-test
Similarly, ink! provides an
examples directory of its
A contract can be compiled from its directory via:
$ cargo +nightly contract build
and tested via:
$ cargo test
Deploy and Interact
CosmWasm contracts are deployed and instantiated with help of the
wasmd executable. The
list of step is provided here.
It is possible to deploy and interact with ink! contracts using either a CLI
cargo-contract), or a web UI (