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page_type: reference
{% comment %}
DO NOT EDIT THIS FILE!
This is generated by the JS SDK team, and any local changes will be
overwritten. Changes should be made in the source code at
https://github.com/firebase/firebase-js-sdk
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# Settings interface
Specifies custom configurations for your Cloud Firestore instance. You must set these before invoking any other methods.
Signature:
```typescript
export declare interface Settings
```
## Properties
| Property | Type | Description |
| --- | --- | --- |
| [grpcFlowControlWindow](./firestore_lite.settings.md#settingsgrpcflowcontrolwindow) | number | Only applicable in Node environments.The gRPC flow control window size in bytes. Defaults to 256 KB. This maps directly to grpc-node's [grpc-node.flow\_control\_window](https://github.com/grpc/grpc-node/blob/651cbeec6b4d6d11cbee91c042946d2fe5968ef6/packages/grpc-js/README.md#supported-channel-options) setting.\*\*WARNING:\*\* This is an advanced setting. The default of 256 KB is optimized for most Node workloads. Only modify this if you are actively tuning gRPC network behavior and understand the implications of HTTP/2 flow control. |
| [host](./firestore_lite.settings.md#settingshost) | string | The hostname to connect to. |
| [ignoreUndefinedProperties](./firestore_lite.settings.md#settingsignoreundefinedproperties) | boolean | Whether to skip nested properties that are set to undefined during object serialization. If set to true, these properties are skipped and not written to Firestore. If set to false or omitted, the SDK throws an exception when it encounters properties of type undefined. |
| [ssl](./firestore_lite.settings.md#settingsssl) | boolean | Whether to use SSL when connecting. |
## Settings.grpcFlowControlWindow
Only applicable in Node environments.
The gRPC flow control window size in bytes. Defaults to 256 KB. This maps directly to grpc-node's [grpc-node.flow\_control\_window](https://github.com/grpc/grpc-node/blob/651cbeec6b4d6d11cbee91c042946d2fe5968ef6/packages/grpc-js/README.md#supported-channel-options) setting.
\*\*WARNING:\*\* This is an advanced setting. The default of 256 KB is optimized for most Node workloads. Only modify this if you are actively tuning gRPC network behavior and understand the implications of HTTP/2 flow control.
Signature:
```typescript
grpcFlowControlWindow?: number;
```
## Settings.host
The hostname to connect to.
Signature:
```typescript
host?: string;
```
## Settings.ignoreUndefinedProperties
Whether to skip nested properties that are set to `undefined` during object serialization. If set to `true`, these properties are skipped and not written to Firestore. If set to `false` or omitted, the SDK throws an exception when it encounters properties of type `undefined`.
Signature:
```typescript
ignoreUndefinedProperties?: boolean;
```
## Settings.ssl
Whether to use SSL when connecting.
Signature:
```typescript
ssl?: boolean;
```