# Interface: `IKernels` [@jupyterlite/kernel](../modules/jupyterlite_kernel.md).IKernels An interface for the Kernels service. ## Properties ### `list` > > **`list`**: () => `Promise`<`IModel`[]\> #### Type declaration > > (): `Promise`<`IModel`[]\> List the running kernels. ##### Returns `Promise`<`IModel`[]\> #### Defined in [packages/kernel/src/tokens.ts:47](https://github.com/jupyterlite/jupyterlite/blob/999c7f0/packages/kernel/src/tokens.ts#L47) ### `restart` > > **`restart`**: (`id`: `string`) => `Promise`<`IModel`\> #### Type declaration > > (`id`): `Promise`<`IModel`\> Restart a kernel. ##### Parameters | Name | Type | Description | | :------ | :------ | :------ | | `id` | `string` | The kernel id. | ##### Returns `Promise`<`IModel`\> #### Defined in [packages/kernel/src/tokens.ts:42](https://github.com/jupyterlite/jupyterlite/blob/999c7f0/packages/kernel/src/tokens.ts#L42) ### `shutdown` > > **`shutdown`**: (`id`: `string`) => `Promise`<`void`\> #### Type declaration > > (`id`): `Promise`<`void`\> Shut down a kernel. ##### Parameters | Name | Type | Description | | :------ | :------ | :------ | | `id` | `string` | The kernel id. | ##### Returns `Promise`<`void`\> #### Defined in [packages/kernel/src/tokens.ts:54](https://github.com/jupyterlite/jupyterlite/blob/999c7f0/packages/kernel/src/tokens.ts#L54) ### `startNew` > > **`startNew`**: (`options`: [`IKernelOptions`](jupyterlite_kernel.Kernels.IKernelOptions.md)) => `Promise`<`IModel`\> #### Type declaration > > (`options`): `Promise`<`IModel`\> Start a new kernel. ##### Parameters | Name | Type | Description | | :------ | :------ | :------ | | `options` | [`IKernelOptions`](jupyterlite_kernel.Kernels.IKernelOptions.md) | The kernel startup options. | ##### Returns `Promise`<`IModel`\> #### Defined in [packages/kernel/src/tokens.ts:35](https://github.com/jupyterlite/jupyterlite/blob/999c7f0/packages/kernel/src/tokens.ts#L35) ## Methods ### `get` > > **`get`**(`id`): `Promise`<`undefined` \| [`IKernel`](jupyterlite_kernel.IKernel-1.md)\> Get a kernel by id #### Parameters | Name | Type | Description | | :------ | :------ | :------ | | `id` | `string` | The kernel id. | #### Returns `Promise`<`undefined` \| [`IKernel`](jupyterlite_kernel.IKernel-1.md)\> the kernel if it exists, undefined otherwise. #### Defined in [packages/kernel/src/tokens.ts:62](https://github.com/jupyterlite/jupyterlite/blob/999c7f0/packages/kernel/src/tokens.ts#L62)