---
title: Upload File
url: https://platform.claude.com/docs/en/api/csharp/files/upload
---

# Upload File

`FileMetadata Files.Upload(parameters, cancellationToken = default)`

**POST** `/v1/files`

Upload File

## Parameters

- `FileUploadParams parameters`

  - `required BinaryContent file`

    The file to upload. Only the final path component of the part's `filename` is kept; an absent or empty `filename` is replaced with `unnamed` plus the extension for the file's stored `mime_type`, when known.

    format: binary

  - `long expiresInSeconds`

    Seconds from upload until the file expires and its bytes become permanently unavailable. Must be between 3600 (one hour) and 7776000 (ninety days).

    minimum: 3600, maximum: 7776000

  - `string workspaceID` (header parameter)

    Optional header to select the Workspace for this request. The value is a Workspace ID (for example, `wrkspc_011CZkZaBF1tNoB5wlCeusgy`).

    Only needed for credentials that can act on more than one Workspace. A credential that belongs to a specific Workspace may omit it; if sent, it must match that Workspace.

## Returns

- `class FileMetadata`

  - `JsonElement Type = "file"`

    Object type.

    For files, this is always `"file"`.

  - `required string ID`

    Unique object identifier.

    The format and length of IDs may change over time.

  - `required DateTimeOffset CreatedAt`

    RFC 3339 datetime string representing when the file was created.

    format: date-time

  - `required string Filename`

    Original filename of the uploaded file.

    minLength: 1, maxLength: 500

  - `required string MimeType`

    MIME type of the file.

    minLength: 1, maxLength: 255

  - `required long SizeBytes`

    Size of the file in bytes.

    minimum: 0

  - `bool Downloadable`

    Whether the file can be downloaded.

  - `DateTimeOffset? ExpiresAt`

    RFC 3339 datetime string representing when the file will expire and become unavailable for download. Null if the file does not expire. For files uploaded with `expires_in_seconds`, this is the upload time plus that value.

    format: date-time

## Example

```csharp
using System;
using System.Text;
using Anthropic.Models.Files;

FileUploadParams parameters = new()
{
    File = Encoding.UTF8.GetBytes("Example data")
};

var fileMetadata = await client.Files.Upload(parameters);

Console.WriteLine(fileMetadata);
```

### Response (200)

```json
{
  "id": "file_011CNha8iCJcU1wXNR6q4V8w",
  "created_at": "2025-04-15T18:37:24.100435Z",
  "filename": "document.pdf",
  "mime_type": "application/pdf",
  "size_bytes": 102400,
  "type": "file",
  "downloadable": false,
  "expires_at": "2025-05-15T18:37:24.100435Z"
}
```