> ## 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.

# Query Error Handling

> Handle missing accounts, NotFound errors, broadcast failures, and timeouts

CosmJS queries can throw errors for various reasons. The high-level clients handle common cases gracefully, but you should be aware of the patterns for each type of failure.

## Missing Accounts

`getAccount` returns `null` when the address has never received tokens. It catches `rpc error: code = NotFound` from the chain and converts it to `null`:

```typescript theme={"system"}
import { StargateClient } from "@cosmjs/stargate";

const client = await StargateClient.connect("https://rpc.my-chain.network");

const account = await client.getAccount("cosmos1unknown...");
if (account === null) {
  console.info("Account does not exist on chain");
}
```

<Note>
  `getSequence` throws if the account does not exist — call `getAccount` first if the address might not be funded.
</Note>

## Missing Delegations

`getDelegation` returns `null` when there is no delegation between the given delegator and validator. It catches `"key not found"` errors:

```typescript theme={"system"}
const delegation = await client.getDelegation("cosmos1...", "cosmosvaloper1...");
if (delegation === null) {
  console.info("No delegation to this validator");
}
```

## NotFound Errors on Extensions

Extension methods do not catch errors automatically. A query for a non-existent resource (e.g., a denom that doesn't exist) throws with a message matching `rpc error: code = NotFound`:

```typescript theme={"system"}
try {
  const metadata = await queryClient.bank.denomMetadata("nonexistent");
} catch (error) {
  if (error instanceof Error && /code = NotFound/i.test(error.message)) {
    console.info("Denomination not found");
  } else {
    throw error;
  }
}
```

## Broadcast Errors

When broadcasting fails at the CheckTx stage, a `BroadcastTxError` is thrown with `code`, `codespace`, and `log` fields. If the transaction is accepted but not included in a block within the timeout, a `TimeoutError` is thrown with the `txId` so you can check later:

```typescript theme={"system"}
import { TimeoutError, BroadcastTxError } from "@cosmjs/stargate";

try {
  const result = await client.broadcastTx(signedTx);
} catch (error) {
  if (error instanceof BroadcastTxError) {
    console.info("Rejected:", error.code, error.codespace, error.log);
  } else if (error instanceof TimeoutError) {
    console.info("Timed out, check later with txId:", error.txId);
  }
}
```

## Next Steps

<CardGroup cols={2}>
  <Card title="Transaction Queries" icon="receipt" href="/cosmjs/v0.38.x/guides/query/transactions">
    Search and decode transactions.
  </Card>

  <Card title="Querying Overview" icon="magnifying-glass" href="/cosmjs/v0.38.x/guides/query/querying">
    All available query methods and extensions.
  </Card>
</CardGroup>