> ## Documentation Index
> Fetch the complete documentation index at: https://docs.neynar.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Detecting chains & capabilities

> Determine which chains and SDK functions a given host supports

Mini Apps are rendered within "hosts" inside web and mobile apps. Not all hosts support the same feature set, but some Mini Apps might require specific features.

If your Mini App requires a given feature, you can declare that feature in your manifest. Alternately, if your Mini App optionally supports a given feature, it can detect the supported set of features at runtime.

## Declaring requirements in your manifest

If your Mini App relies on certain blockchains or SDK methods, you can declare those in your manifest via the properties `requiredChains` and `requiredCapabilities`.

### `requiredChains`

`miniapp.requiredChains` is an optional [manifest](/miniapps/guides/publishing#host-a-manifest-file) property that contains an array of [CAIP-2](https://github.com/ChainAgnostic/CAIPs/blob/main/CAIPs/caip-2.md) identifiers. If the host does not support all of the chains declared here, it will know not to try rendering your Mini App.

Note that only the chains listed in `chainList` [here](https://github.com/farcasterxyz/miniapps/blob/main/packages/miniapp-core/src/schemas/manifest.ts) are supported. If your manifest omits `requiredChains`, then the mini app host will assume that no chains are required.

### `requiredCapabilities`

`miniapp.requiredCapabilities` is an optional [manifest](/miniapps/guides/publishing#host-a-manifest-file) property that contains an array of paths to SDK methods, such as `wallet.getEthereumProvider` or `actions.composeCast`. If the host does not support all of the capabilities declared here, it will know not to try rendering your Mini App.

The full list of supported SDK methods can be found in `miniAppHostCapabilityList` [here](https://github.com/farcasterxyz/miniapps/blob/main/packages/miniapp-core/src/types.ts). If your manifest omits `requiredCapabilities`, then the mini app host will assume that no capabilities are required.

## Runtime detection

If your Mini App optionally supports certain blockchains or SDK methods, you can detect whether they are supported at runtime via SDK calls.

### `getChains`

This SDK method returns a list of supported blockchains as an array of [CAIP-2](https://github.com/ChainAgnostic/CAIPs/blob/main/CAIPs/caip-2.md) identifiers.

### `getCapabilities`

This SDK method returns a list of supported SDK methods as an array of paths to those SDK methods. The full list of supported SDK methods can be found in `miniAppHostCapabilityList` [here](https://github.com/farcasterxyz/miniapps/blob/main/packages/miniapp-core/src/types.ts).

#### Example

```ts theme={"system"}
import { sdk } from '@farcaster/miniapp-sdk'

// Get all supported capabilities
const capabilities = await sdk.getCapabilities()

// Check for specific capabilities
const supportsCompose = capabilities.includes('actions.composeCast')
const supportsWallet = capabilities.includes('wallet.getEthereumProvider')

// Check for haptics support
const supportsHaptics = {
  impact: capabilities.includes('haptics.impactOccurred'),
  notification: capabilities.includes('haptics.notificationOccurred'),
  selection: capabilities.includes('haptics.selectionChanged')
}

// Use capabilities conditionally
if (supportsHaptics.impact) {
  await sdk.haptics.impactOccurred('medium')
}
```