[Home](./index.md) > [@firebase/storage](./storage.md) > [UploadMetadata](./storage.uploadmetadata.md) ## UploadMetadata interface Object metadata that can be set at upload. Signature: ```typescript export interface UploadMetadata extends SettableMetadata ``` Extends: [SettableMetadata](./storage.settablemetadata.md) ## Properties | Property | Type | Description | | --- | --- | --- | | [md5Hash?](./storage.uploadmetadata.md5hash.md) | string \| undefined | (Optional) A Base64-encoded MD5 hash of the object being uploaded. |