# SignatureEnvelope.assert

Asserts that a [`SignatureEnvelope.SignatureEnvelope`](/tempo/reference/SignatureEnvelope/types#signatureenvelope) is valid.

## Imports

:::code-group
```ts [Named]
import { SignatureEnvelope } from 'ox/tempo'
```

```ts [Entrypoint]
import * as SignatureEnvelope from 'ox/tempo/SignatureEnvelope'
```
:::

## Examples

```ts twoslash
import { SignatureEnvelope } from 'ox/tempo'

SignatureEnvelope.assert({
  type: 'secp256k1',
  signature: {
    r: '0x0000000000000000000000000000000000000000000000000000000000000000',
    s: '0x0000000000000000000000000000000000000000000000000000000000000000',
    yParity: 0
  }
})
```

## Definition

```ts
function assert(
  envelope: PartialBy<SignatureEnvelope, 'type'>,
): void
```

**Source:** [src/tempo/SignatureEnvelope.ts](https://github.com/wevm/ox/blob/main/src/tempo/SignatureEnvelope.ts#L1794)

## Parameters

### envelope

* **Type:** `PartialBy<SignatureEnvelope, 'type'>`

The signature envelope to assert.

## Return Type

`void`