Agent Setup

info

This guide assumes you have followed the Prerequisites, and you have a valid Node.js or React Native project setup.

caution

Credo is still in active development, and as such some APIs are still experimental. When using any experimental features, make sure to use an exact version of Credo (0.5.0) instead of a range (^0.5.0), to prevent accidental breaking changes. If you're not leveraging any experimental features, you can use a range (^0.5.0) to get the latest bugfixes and features.

For Credo 0.5.x, the following features are experimental:

• Using OpenID4VC from the @credo-ts/openid4vc module
• SD-JWT Verifiable Credentials
• Using multi-tenancy from the @credo-ts/tenants module
• Using BBS+ Signatures from the @credo-ts/bbs-signatures module
• Using the cheqd module from the @credo-ts/cheqd module
• Using DIF Presentation Exchange
• Using AnonCreds in the W3C Verifiable Credential format

Installing the required dependencies

First we have to install the minimal amount of dependencies that are required for configuring an Credo agent.

Node.js

yarn add @credo-ts/core@^0.5.3 @credo-ts/node@^0.5.3

React Native

yarn add @credo-ts/core@^0.5.3 @credo-ts/react-native@^0.5.3 react-native-fs react-native-get-random-values

Additional setup

Node.js

No additional setup is required for Node.js

React Native

Since React Native does not have an implementation for crypto.getRandomValues() we have to setup a polyfill for this. We have to do this at the entrypoint of the application. This could is most likely index.(js|ts|jsx|tsx) at the root of your application.

index.tsx

+ import 'react-native-get-random-values'

In addition you need add support for resolving modules with the .cjs extension, as this is used by some of Credo's dependencies and not automatically supported by React Native.

metro.config.js

module.exports = {
  // ... other Metro config options ...
  resolver: {
    // make sure this includes `cjs` (and other extensions you need)
    sourceExts: ['js', 'json', 'ts', 'tsx', 'cjs'],
  },
}

Finally, if you're using Expo you need to add a custom resolution 'hack' that removes support for the legacy unimodules.

Yarn

For yarn we can replace the @unimodules/react-native-adapter and @unimodules/core dependencies with an empty directory. Make sure to create the noop directory in the root of your project and create a .gitkeep file in the directory so that the directory is committed to your repository.

package.json

{
  // ... other package.json options ...
  "resolutions": {
    "@unimodules/react-native-adapter": "./noop",
    "@unimodules/core": "./noop"
  }
}

NPM

Not supported at the moment. NPM overrides work different than Yarn resolutions, and thus we can't use the same trick. If you're using NPM, feel free to open a PR with a working solution.

Setting up the agent

this section does not assume any knowledge of the agent configuration. In the Agent Config tutorial we will discuss in-depth what every field in the configuration does and when to set it.

In order to use the agent in the application we have to configure and initialize it. This following configuration is quite generic and possibly not enough for your specific use cases. Please refer to the tutorials for a more use-case-specific agent setup.

Node.js

import type { InitConfig } from '@credo-ts/core'
import { Agent } from '@credo-ts/core'
import { agentDependencies } from '@credo-ts/node'

const config: InitConfig = {
  label: 'docs-agent-nodejs',
  walletConfig: {
    id: 'wallet-id',
    key: 'testkey0000000000000000000000000',
  },
}

const agent = new Agent({
  config,
  dependencies: agentDependencies,
})

React Native

import type { InitConfig } from '@credo-ts/core'
import { Agent } from '@credo-ts/core'
import { agentDependencies } from '@credo-ts/react-native'

const config: InitConfig = {
  label: 'docs-agent-react-native',
  walletConfig: {
    id: 'wallet-id',
    key: 'testkey0000000000000000000000000',
  },
}

const agent = new Agent({
  config,
  dependencies: agentDependencies,
})

Adding a wallet and storage implementation

After creating the Agent instance, we need to provide the agent with a wallet and storage implementation. Credo provides one implementations out of the box, but you can also implement your own. Currently a Wallet and Storage implementation using Aries Askar is supported out of the box.

• Aries Askar

📄️ Aries Askar

Aries Askar provides secure, encrypted storage and cryptographic support for encrypting, decrypting, signing and verifying data. It also provides both the Wallet and StorageService implementations for the agent.

Setting up the transports

Finally, we have to set an outbound transport that will handle traffic from the agent. It is also possible to set an inbound transport in the same way as the outbound transport.

Node.js

Sets up an WS outbound and HTTP inbound and outbound transport.

import { HttpOutboundTransport, WsOutboundTransport } from '@credo-ts/core'
import { HttpInboundTransport } from '@credo-ts/node'

// ... agent setup from prevous section ...

agent.registerOutboundTransport(new HttpOutboundTransport())
agent.registerOutboundTransport(new WsOutboundTransport())
agent.registerInboundTransport(new HttpInboundTransport({ port: 3000 }))

React Native

For mobile agents the WebSocket transport is often required. We will go into more depth about the reasons for this in the mediation section.

import { HttpOutboundTransport, WsOutboundTransport } from '@credo-ts/core'

// ... agent setup from prevous section ...

agent.registerOutboundTransport(new HttpOutboundTransport())
agent.registerOutboundTransport(new WsOutboundTransport())

Initializing the agent

Finally, we can initialize the agent and it's ready for use.

Node.js

agent
  .initialize()
  .then(() => {
    console.log('Agent initialized!')
  })
  .catch((e) => {
    console.error(`Something went wrong while setting up the agent! Message: ${e}`)
  })

React Native

agent
  .initialize()
  .then(() => {
    console.log('Agent initialized!')
  })
  .catch((e) => {
    console.error(`Something went wrong while setting up the agent! Message: ${e}`)
  })

Next Steps

Now that you have your agent setup, it's time to start building your application. Head over to the tutorials page to get started.

📄️ Tutorials

In this section we will explain some features that everyone will use. This

📄️ Create a Connection

In this tutorial we will create a connection as Acme Corp with Bob. We will

Useful resources

• Hyperledger Aries RFC - 004: Agents