CosmJS is the Swiss Army knife to power JavaScript based client solutions ranging from Web apps/explorers over browser extensions to server-side clients like faucets/scrapers in the Cosmos ecosystem.

"Cosm" is short for Cosmos and "JS" is short for runs everywhere – we actually develop in TypeScript.

Here is a list of examples using the Stargate package for use with Cosmos SDK 0.41 applications (like gaia 4). Take a look at the wiki page, "What can CosmJS do for me?" and various tests (ex) for more example usage of the packages.

The full API documentation is hosted at cosmos.github.io/cosmjs. This is a bit tricky to navigate and requires basic TypeScript understanding. It is helpful if you want to look up details for advanced use cases. This documentation is auto-generated based on the current main branch and can occasionally diverge from the latest release.

Documentation on how to use your own custom modules with CosmJS for Stargate chains (Cosmos SDK v0.41) can be found here.

CosmJS is a library that consists of many smaller npm packages within the @cosmjs namespace, a so-called monorepo. Here are some of them to get an idea:

Package	Description	Latest
@cosmjs/stargate	A client library for the Cosmos SDK 0.40+ (Stargate)
@cosmjs/faucet	A faucet application for node.js
@cosmjs/cosmwasm-stargate	Client for Stargate chains with the CosmWasm module enabled
@cosmjs/crypto	Cryptography for blockchain projects, e.g. hashing (SHA-2, Keccak256, Ripemd160), signing (secp256k1, ed25519), HD key derivation (BIP-39, SLIP-0010), KDFs and symmetric encryption for key storage (PBKDF2, Argon2, XChaCha20Poly1305)
@cosmjs/encoding	Encoding helpers for blockchain projects
@cosmjs/math	Safe integers; decimals for handling financial amounts

We're pretty proud of the modularity and a clean dependency tree in this monorepo. This ensures software quality on our side and lets users pick exactly what they need. Here you see how everything fits together (every item is a npm package; right depends on left):

If this was not enough to scare you away, check out the version including app runtime dependencies: cosmjs-tree-full.png.

Currently the codebase supports the following runtime environments:

1. Node.js 14+
2. Modern browsers (Chromium/Firefox/Safari, no Internet Explorer or Edge Spartan)
3. Browser extensions (Chromium/Firefox)

Our current JavaScript target standard is ES2020. We use WebAssembly to implement certain cryptographic functions.

We're happy to adjust this list according to users' needs as long as you don't ask for Internet Explorer support. If your environment does not support Wasm, we can work on a solution with swappable implementations.

With WebPack 5, you have to be explicit about the usage of Node.js types and modules that were simply replaced with re-implementations for browsers in Webpack 4.

Configs for 0.28 and later:

module.exports = [
  {
    // ...
    plugins: [
      ...,
      new webpack.ProvidePlugin({
        Buffer: ["buffer", "Buffer"],
      }),
    ],
    // ...
    resolve: {
      fallback: {
        buffer: false,
        crypto: false,
        events: false,
        path: false,
        stream: false,
        string_decoder: false,
      },
    },
  },
];

Configs for CosmJS < 0.28

module.exports = [
  {
    // ...
    plugins: [
      ...,
      new webpack.ProvidePlugin({
        Buffer: ["buffer", "Buffer"],
      }),
    ],
    // ...
    resolve: {
      fallback: {
        buffer: false,
        crypto: false,
        events: false,
        path: false,
        stream: require.resolve("stream-browserify"),
        string_decoder: false,
      },
    },
  },
];

We maintain a development board, use release milestones and share important updates in the CosmWasm Community Call. For higher level roadmap discussion please reach out to the team.

1. When connecting to a Cosmos SDK 0.44+ backend, the verified queries from AuthExtension and BankExtension as well as StargateClient.getAccountVerified will fail because the storage keys are not stable. Unverified queries can be used instead. Those queries are deprecated now and will be removed in 0.27 (#910).

1. Decoding blocks of height 1 is unsupported. This is fixed in #815 and will be released as part of CosmJS 0.26.

1. AuthExtension and all higher level Stargate clients only support BaseAccounts for all functionality, including getting account numbers and sequences for transaction signing. This will be implemented for all common Cosmos SDK account types in the 0.25 series.

The CosmJS development team is happy to get in touch with you for all questions and suggestions.

• GitHub issues for bugs and feature requests
• The #cosmjs channel on the "Cosmos Community" Discord server for questions and open discussions
• #CosmJS on Twitter to spread the word

See HACKING.md.