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

# Version Detection

> How CosmJS auto-detects CometBFT versions and how to skip the detection round-trip

When you call `StargateClient.connect()` or `connectComet()`, CosmJS auto-detects the node's CometBFT version so it can use the correct RPC protocol.

## How Auto-Detection Works

<Steps>
  <Step title="Initial connection">
    CosmJS connects a Tendermint 0.37 client and calls `status()`.
  </Step>

  <Step title="Version check">
    It reads `nodeInfo.version` from the response.
  </Step>

  <Step title="Client selection">
    If the version starts with `0.38.`, it disconnects and reconnects with `Comet38Client`. If it starts with `1.`, it reconnects with `Comet1Client`. Otherwise, it keeps the 0.37 client.
  </Step>
</Steps>

This costs one extra RPC round-trip on startup.

## Skipping Auto-Detection

If you already know your chain's CometBFT version, skip auto-detection by constructing the client directly:

```typescript theme={"system"}
import { StargateClient } from "@cosmjs/stargate";
import { Comet1Client, HttpClient } from "@cosmjs/tendermint-rpc";

const rpcClient = new HttpClient("https://rpc.my-chain.network");
const cometClient = Comet1Client.create(rpcClient);
const client = StargateClient.create(cometClient);
```

<Tip>
  Skipping auto-detection saves one RPC round-trip on every client creation. This is worth doing in production when you know the chain's CometBFT version.
</Tip>

## Using `connectComet` Directly

You can also use `connectComet` on its own when you need a `CometClient` without a high-level wrapper:

```typescript theme={"system"}
import { connectComet } from "@cosmjs/tendermint-rpc";

const cometClient = await connectComet("https://rpc.my-chain.network");
const status = await cometClient.status();
```

## Next Steps

<CardGroup cols={2}>
  <Card title="Connect to a Chain" icon="link" href="/cosmjs/v0.38.x/guides/connect/connect">
    Return to the connection overview and transport selection table.
  </Card>

  <Card title="Custom Endpoints" icon="key" href="/cosmjs/v0.38.x/guides/connect/custom-endpoints">
    Combine manual client construction with custom headers and batching.
  </Card>
</CardGroup>