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Files API

The Files API lets you upload and manage files to use with the Claude API without re-uploading content with each request. This is particularly useful when using the code execution tool to provide inputs (e.g. datasets and documents) and then download outputs (e.g. charts). You can also use the Files API to prevent having to continually re-upload frequently used documents and images across multiple API calls. You can explore the API reference directly, in addition to this guide.

Note

The Files API is in beta. Reach out through the feedback form to share your experience with the Files API.

Note

This feature is not eligible for Zero Data Retention (ZDR). Data is retained according to the feature's standard retention policy.

Supported models

Referencing a file_id in a Messages request is supported on all models that support the given file type. Images are supported on all current Claude models. For PDFs and other file types with the code execution tool, see the linked pages for model support.

The Files API is available on the Claude API, Claude Platform on AWS, and Microsoft Foundry. It is not currently available on Amazon Bedrock or Vertex AI.

How the Files API works

The Files API provides a simple create-once, use-many-times approach for working with files:

  • Upload files to Anthropic's secure storage and receive a unique file_id
  • Download files that are created from skills or the code execution tool
  • Reference files in Messages requests using the file_id instead of re-uploading content
  • Manage your files with list, retrieve, and delete operations

How to use the Files API

Note

To use the Files API, you'll need to include the beta feature header: anthropic-beta: files-api-2025-04-14.

Uploading a file

Upload a file to be referenced in future API calls:

curl -X POST https://api.anthropic.com/v1/files \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "anthropic-beta: files-api-2025-04-14" \
  -F "file=@/path/to/document.pdf"

FILE_ID=$(ant beta:files upload \
  --file /path/to/document.pdf \
  --transform id --raw-output)

uploaded = client.beta.files.upload(
    file=("document.pdf", open("/path/to/document.pdf", "rb"), "application/pdf"),
)

const uploaded = await client.beta.files.upload({
  file: await toFile(
    fs.createReadStream("/path/to/document.pdf"),
    undefined,
    { type: "application/pdf" },
  ),
});

var uploaded = await client.Beta.Files.Upload(
    new FileUploadParams
    {
        File = new BinaryContent
        {
            Stream = File.OpenRead("/path/to/document.pdf"),
            FileName = "document.pdf",
            ContentType = new("application/pdf")
        }
    });

Console.WriteLine(uploaded.ID);

f, err := os.Open("/path/to/document.pdf")
if err != nil {
	log.Fatal(err)
}
defer f.Close()

response, err := client.Beta.Files.Upload(context.Background(),
	anthropic.BetaFileUploadParams{
		File: anthropic.File(f, "document.pdf", "application/pdf"),
	})
if err != nil {
	log.Fatal(err)
}

fmt.Println(response.ID)

FileMetadata file = client.beta().files().upload(
    FileUploadParams.builder()
        .file(MultipartField.<InputStream>builder()
            .value(Files.newInputStream(Path.of("/path/to/document.pdf")))
            .filename("document.pdf")
            .contentType("application/pdf")
            .build())
        .build()
);

System.out.println(file.id());

$file = $client->beta->files->upload(
    FileParam::fromResource(fopen('/path/to/document.pdf', 'rb'), contentType: 'application/pdf'),
);

echo $file->id;

file = client.beta.files.upload(
  file: Anthropic::FilePart.new(
    Pathname("/path/to/document.pdf"),
    content_type: "application/pdf"
  )
)

puts file.id

The response from uploading a file will include:

{
  "id": "file_011CNha8iCJcU1wXNR6q4V8w",
  "type": "file",
  "filename": "document.pdf",
  "mime_type": "application/pdf",
  "size_bytes": 1024000,
  "created_at": "2025-01-01T00:00:00Z",
  "downloadable": false
}

Using a file in messages

Once uploaded, reference the file using its file_id:

curl -X POST https://api.anthropic.com/v1/messages \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "anthropic-beta: files-api-2025-04-14" \
  -H "content-type: application/json" \
  -d @- <<EOF
{
  "model": "claude-opus-4-6",
  "max_tokens": 1024,
  "messages": [
    {
      "role": "user",
      "content": [
        {
          "type": "text",
          "text": "Please summarize this document for me."
        },
        {
          "type": "document",
          "source": {
            "type": "file",
            "file_id": "$FILE_ID"
          }
        }
      ]
    }
  ]
}
EOF

ant beta:messages create --beta files-api-2025-04-14 <<YAML
model: claude-opus-4-6
max_tokens: 1024
messages:
  - role: user
    content:
      - type: text
        text: Please summarize this document for me.
      - type: document
        source:
          type: file
          file_id: $FILE_ID
YAML

response = client.beta.messages.create(
    model="claude-opus-4-6",
    max_tokens=1024,
    messages=[
        {
            "role": "user",
            "content": [
                {"type": "text", "text": "Please summarize this document for me."},
                {
                    "type": "document",
                    "source": {
                        "type": "file",
                        "file_id": file_id,
                    },
                },
            ],
        }
    ],
    betas=["files-api-2025-04-14"],
)
print(response)

const response = await client.beta.messages.create({
  model: "claude-opus-4-6",
  max_tokens: 1024,
  messages: [
    {
      role: "user",
      content: [
        {
          type: "text",
          text: "Please summarize this document for me.",
        },
        {
          type: "document",
          source: {
            type: "file",
            file_id: uploaded.id,
          },
        },
      ],
    },
  ],
  betas: ["files-api-2025-04-14"],
});

console.log(response);

var response = await client.Beta.Messages.Create(
    new MessageCreateParams
    {
        Model = Messages::Model.ClaudeOpus4_6,
        MaxTokens = 1024,
        Betas = [AnthropicBeta.FilesApi2025_04_14],
        Messages =
        [
            new BetaMessageParam
            {
                Role = Role.User,
                Content = new List<BetaContentBlockParam>
                {
                    new BetaTextBlockParam { Text = "Please summarize this document for me." },
                    new BetaRequestDocumentBlock
                    {
                        Source = new BetaFileDocumentSource { FileID = fileId }
                    }
                }
            }
        ]
    });

Console.WriteLine(response);

msg, err := client.Beta.Messages.New(context.Background(),
	anthropic.BetaMessageNewParams{
		Model:     anthropic.ModelClaudeOpus4_6,
		MaxTokens: 1024,
		Betas:     []anthropic.AnthropicBeta{anthropic.AnthropicBetaFilesAPI2025_04_14},
		Messages: []anthropic.BetaMessageParam{
			anthropic.NewBetaUserMessage(
				anthropic.NewBetaTextBlock("Please summarize this document for me."),
				anthropic.NewBetaDocumentBlock(anthropic.BetaFileDocumentSourceParam{
					FileID: fileID,
				}),
			),
		},
	})
if err != nil {
	log.Fatal(err)
}

fmt.Println(msg)

MessageCreateParams params = MessageCreateParams.builder()
    .model(Model.CLAUDE_OPUS_4_6)
    .addBeta("files-api-2025-04-14")
    .maxTokens(1024)
    .addUserMessageOfBetaContentBlockParams(List.of(
        BetaContentBlockParam.ofText(BetaTextBlockParam.builder()
            .text("Please summarize this document for me.")
            .build()),
        BetaContentBlockParam.ofDocument(BetaRequestDocumentBlock.builder()
            .source(BetaFileDocumentSource.builder()
                .fileId(fileId)
                .build())
            .build())
    ))
    .build();

BetaMessage message = client.beta().messages().create(params);
System.out.println(message);

$response = $client->beta->messages->create(
    maxTokens: 1024,
    messages: [
        [
            'role' => 'user',
            'content' => [
                ['type' => 'text', 'text' => 'Please summarize this document for me.'],
                [
                    'type' => 'document',
                    'source' => [
                        'type' => 'file',
                        'file_id' => $fileId
                    ]
                ]
            ]
        ]
    ],
    model: 'claude-opus-4-6',
    betas: ['files-api-2025-04-14'],
);

print_r($response);

response = client.beta.messages.create(
  model: "claude-opus-4-6",
  max_tokens: 1024,
  betas: ["files-api-2025-04-14"],
  messages: [
    {
      role: "user",
      content: [
        { type: "text", text: "Please summarize this document for me." },
        {
          type: "document",
          source: {
            type: "file",
            file_id: file_id
          }
        }
      ]
    }
  ]
)

puts response

File types and content blocks

The Files API supports different file types that correspond to different content block types:

File TypeMIME TypeContent Block TypeUse Case
PDFapplication/pdfdocumentText analysis, document processing
Plain texttext/plaindocumentText analysis, processing
Imagesimage/jpeg, image/png, image/gif, image/webpimageImage analysis, visual tasks
Datasets, othersVariescontainer_uploadAnalyze data, create visualizations

Working with other file formats

For file types that are not supported as document blocks (.csv, .txt, .md, .docx, .xlsx), convert the files to plain text, and include the content directly in your message:

# Example: Reading a text file and sending it as plain text
# Note: For files with special characters, consider base64 encoding
TEXT_CONTENT="This is a sample document. It has multiple lines."

curl https://api.anthropic.com/v1/messages \
  -H "content-type: application/json" \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -d @- <<EOF
{
  "model": "claude-opus-4-7",
  "max_tokens": 1024,
  "messages": [
    {
      "role": "user",
      "content": [
        {
          "type": "text",
          "text": "Here's the document content:\n\n${TEXT_CONTENT}\n\nPlease summarize this document."
        }
      ]
    }
  ]
}
EOF

printf 'This is a test document for upload.\n' > document.txt
# The "@./path" reference inlines the file contents directly into the field.
ant messages create \
  --model claude-opus-4-7 \
  --max-tokens 1024 \
  --transform 'content.0.text' --raw-output <<'YAML'
messages:
  - role: user
    content:
      - type: text
        text: "Here's the document content:"
      - type: text
        text: "@./document.txt"
      - type: text
        text: "Please summarize this document."
YAML

import pandas as pd
import anthropic

client = anthropic.Anthropic()

# Example: Reading a CSV file
df = pd.read_csv("data.csv")
csv_content = df.to_string()

# Send as plain text in the message
response = client.messages.create(
    model="claude-opus-4-7",
    max_tokens=1024,
    messages=[
        {
            "role": "user",
            "content": [
                {
                    "type": "text",
                    "text": f"Here's the CSV data:\n\n{csv_content}\n\nPlease analyze this data.",
                }
            ],
        }
    ],
)

print(response.content[0].text)

import Anthropic from "@anthropic-ai/sdk";
import fs from "fs/promises";

const anthropic = new Anthropic();

async function analyzeDocument() {
  // Example: Reading a text file
  const textContent = await fs.readFile("document.txt", "utf-8");

  // Send as plain text in the message
  const response = await anthropic.messages.create({
    model: "claude-opus-4-7",
    max_tokens: 1024,
    messages: [
      {
        role: "user",
        content: [
          {
            type: "text",
            text: `Here's the document content:\n\n${textContent}\n\nPlease summarize this document.`
          }
        ]
      }
    ]
  });

  const block = response.content[0];
  if (block.type === "text") {
    console.log(block.text);
  }
}

analyzeDocument();

using System;
using System.IO;
using System.Threading.Tasks;
using Anthropic;
using Anthropic.Models.Messages;

class Program
{
    static async Task Main(string[] args)
    {
        AnthropicClient client = new();

        // Example: Reading a text file
        string textContent = await File.ReadAllTextAsync("document.txt");

        var parameters = new MessageCreateParams
        {
            Model = Model.ClaudeOpus4_7,
            MaxTokens = 1024,
            Messages = [new()
            {
                Role = Role.User,
                Content = {{CONTENT}}quot;Here's the document content:\n\n{textContent}\n\nPlease summarize this document."
            }]
        };

        var message = await client.Messages.Create(parameters);
        Console.WriteLine(message);
    }
}

package main

import (
	"context"
	"fmt"
	"log"
	"os"

	"github.com/anthropics/anthropic-sdk-go"
)

func init() {
	os.WriteFile("document.txt", []byte("This is a test document for upload."), 0644)
}

func main() {
	client := anthropic.NewClient()

	// Example: Reading a text file
	textContent, err := os.ReadFile("document.txt")
	if err != nil {
		log.Fatal(err)
	}

	response, err := client.Messages.New(context.TODO(), anthropic.MessageNewParams{
		Model:     anthropic.ModelClaudeOpus4_7,
		MaxTokens: 1024,
		Messages: []anthropic.MessageParam{
			anthropic.NewUserMessage(anthropic.NewTextBlock(
				fmt.Sprintf("Here's the document content:\n\n%s\n\nPlease summarize this document.", string(textContent)),
			)),
		},
	})
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(response.Content[0].Text)
}

import com.anthropic.client.AnthropicClient;
import com.anthropic.client.okhttp.AnthropicOkHttpClient;
import com.anthropic.models.messages.MessageCreateParams;
import com.anthropic.models.messages.Message;
import com.anthropic.models.messages.Model;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.io.IOException;

public class FileUploadExample {
    public static void main(String[] args) throws IOException {
        AnthropicClient client = AnthropicOkHttpClient.fromEnv();

        // Example: Reading a text file
        String textContent = Files.readString(Paths.get("document.txt"));

        MessageCreateParams params = MessageCreateParams.builder()
            .model(Model.CLAUDE_OPUS_4_7)
            .maxTokens(1024L)
            .addUserMessage("Here's the document content:\n\n" + textContent + "\n\nPlease summarize this document.")
            .build();

        Message response = client.messages().create(params);
        response.content().stream()
            .flatMap(block -> block.text().stream())
            .forEach(textBlock -> System.out.println(textBlock.text()));
    }
}

<?php

use Anthropic\Client;

$client = new Client(apiKey: getenv("ANTHROPIC_API_KEY"));

// Example: Reading a text file
$textContent = file_get_contents("document.txt");

$message = $client->messages->create(
    maxTokens: 1024,
    messages: [
        [
            'role' => 'user',
            'content' => [
                [
                    'type' => 'text',
                    'text' => "Here's the document content:\n\n{$textContent}\n\nPlease summarize this document."
                ]
            ]
        ]
    ],
    model: 'claude-opus-4-7',
);

echo $message->content[0]->text;

require "anthropic"

client = Anthropic::Client.new

# Example: Reading a text file
text_content = File.read("document.txt")

message = client.messages.create(
  model: "claude-opus-4-7",
  max_tokens: 1024,
  messages: [
    {
      role: "user",
      content: [
        {
          type: "text",
          text: "Here's the document content:\n\n#{text_content}\n\nPlease summarize this document."
        }
      ]
    }
  ]
)

puts message.content.first.text
Note

For .docx files containing images, convert them to PDF format first, then use PDF support to take advantage of the built-in image parsing. This allows using citations from the PDF document.

Document blocks

For PDFs and text files, use the document content block:

{
  "type": "document",
  "source": {
    "type": "file",
    "file_id": "file_011CNha8iCJcU1wXNR6q4V8w"
  },
  "title": "Document Title", // Optional
  "context": "Context about the document", // Optional
  "citations": { "enabled": true } // Optional, enables citations
}

Image blocks

For images, use the image content block:

{
  "type": "image",
  "source": {
    "type": "file",
    "file_id": "file_011CPMxVD3fHLUhvTqtsQA5w"
  }
}

Managing files

List files

Retrieve a list of your uploaded files:

curl https://api.anthropic.com/v1/files \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "anthropic-beta: files-api-2025-04-14"

ant beta:files list

import anthropic

client = anthropic.Anthropic()
files = client.beta.files.list()

import Anthropic from "@anthropic-ai/sdk";

const anthropic = new Anthropic();
const files = await anthropic.beta.files.list();

using System;
using System.Threading.Tasks;
using Anthropic;
using Anthropic.Models.Beta.Files;

class Program
{
    static async Task Main(string[] args)
    {
        AnthropicClient client = new();

        var files = await client.Beta.Files.List();
        Console.WriteLine(files);
    }
}

package main

import (
	"context"
	"fmt"
	"log"

	"github.com/anthropics/anthropic-sdk-go"
)

func main() {
	client := anthropic.NewClient()

	files, err := client.Beta.Files.List(context.TODO(), anthropic.BetaFileListParams{})
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println(files)
}

import com.anthropic.client.AnthropicClient;
import com.anthropic.client.okhttp.AnthropicOkHttpClient;
import com.anthropic.models.beta.files.FileListPage;

public class ListFiles {
    public static void main(String[] args) {
        AnthropicClient client = AnthropicOkHttpClient.fromEnv();

        FileListPage files = client.beta().files().list();
        System.out.println(files);
    }
}

<?php

use Anthropic\Client;

$client = new Client(apiKey: getenv("ANTHROPIC_API_KEY"));

$files = $client->beta->files->list();
print_r($files);

require "anthropic"

client = Anthropic::Client.new

files = client.beta.files.list
puts files

Get file metadata

Retrieve information about a specific file:

curl "https://api.anthropic.com/v1/files/$FILE_ID" \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "anthropic-beta: files-api-2025-04-14"

ant beta:files retrieve-metadata \
  --file-id "$FILE_ID"

file = client.beta.files.retrieve_metadata(file_id)

const file = await client.beta.files.retrieveMetadata(uploaded.id);

var file = await client.Beta.Files.RetrieveMetadata(fileId);
Console.WriteLine(file);

metadata, err := client.Beta.Files.GetMetadata(
	context.TODO(),
	fileID,
	anthropic.BetaFileGetMetadataParams{},
)
if err != nil {
	log.Fatal(err)
}

fmt.Println(metadata)

FileMetadata metadata = client.beta().files().retrieveMetadata(fileId);

System.out.println(metadata);

$file = $client->beta->files->retrieveMetadata($fileId);
echo $file;

file = client.beta.files.retrieve_metadata(file_id)
puts file

Delete a file

Remove a file from your workspace:

curl -X DELETE "https://api.anthropic.com/v1/files/$FILE_ID" \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "anthropic-beta: files-api-2025-04-14"

ant beta:files delete \
  --file-id "$FILE_ID"

result = client.beta.files.delete(file_id)

await client.beta.files.delete(uploaded.id);

await client.Beta.Files.Delete(fileId);

_, err = client.Beta.Files.Delete(
	context.TODO(),
	fileID,
	anthropic.BetaFileDeleteParams{},
)
if err != nil {
	log.Fatal(err)
}

client.beta().files().delete(fileId);

$result = $client->beta->files->delete($fileId);

result = client.beta.files.delete(file_id)

Downloading a file

Download files that have been created by skills or the code execution tool:

curl -X GET "https://api.anthropic.com/v1/files/$FILE_ID/content" \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "anthropic-beta: files-api-2025-04-14" \
  --output downloaded_file.txt

ant beta:files download \
  --file-id "$FILE_ID" \
  --output downloaded_file.txt

file_content = client.beta.files.download(file_id)

# Save to file
file_content.write_to_file("downloaded_file.txt")

const content = await client.beta.files.download(uploaded.id);

const bytes = Buffer.from(await content.arrayBuffer());
await fsp.writeFile("downloaded_file.txt", bytes);

using var fileContent = await client.Beta.Files.Download(fileId);
await using var source = await fileContent.ReadAsStream();
await using var destination = File.Create("downloaded_file.txt");
await source.CopyToAsync(destination);

func downloadFile(client anthropic.Client, fileID string) error {
	resp, err := client.Beta.Files.Download(
		context.TODO(),
		fileID,
		anthropic.BetaFileDownloadParams{},
	)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

	fileContent, err := io.ReadAll(resp.Body)
	if err != nil {
		return err
	}

	return os.WriteFile("downloaded_file.txt", fileContent, 0644)
}


try (HttpResponse response = client.beta().files().download(fileId)) {
    try (InputStream body = response.body()) {
        Files.copy(body, Path.of("downloaded_file.txt"),
            StandardCopyOption.REPLACE_EXISTING);
    }
}

$fileContent = $client->beta->files->download($fileId);

file_put_contents("downloaded_file.txt", $fileContent);

file_content = client.beta.files.download(file_id)

File.binwrite("downloaded_file.txt", file_content.read)
Note

You can only download files that were created by skills or the code execution tool. Files that you uploaded cannot be downloaded.

File storage and limits

Storage limits

  • Maximum file size: 500 MB per file
  • Total storage: 500 GB per organization

File lifecycle

  • Files are scoped to the workspace of the API key. Other API keys can use files created by any other API key associated with the same workspace
  • Files persist until you delete them
  • Deleted files cannot be recovered
  • Files are inaccessible via the API shortly after deletion, but they may persist in active Messages API calls and associated tool uses
  • Files that users delete will be deleted in accordance with Anthropic's data retention policy.

Data retention

Files uploaded via the Files API are retained until explicitly deleted using the DELETE /v1/files/{file_id} endpoint. Files are stored for reuse across multiple API requests.

For ZDR eligibility across all features, see API and data retention.

Error handling

Common errors when using the Files API include:

  • File not found (404): The specified file_id doesn't exist or you don't have access to it
  • Invalid file type (400): The file type doesn't match the content block type (e.g., using an image file in a document block)
  • Exceeds context window size (400): The file is larger than the context window size (e.g. using a 500 MB plaintext file in a /v1/messages request)
  • Invalid filename (400): Filename doesn't meet the length requirements (1-255 characters) or contains forbidden characters (<, >, :, ", |, ?, *, \, /, or unicode characters 0-31)
  • File too large (413): File exceeds the 500 MB limit
  • Storage limit exceeded (403): Your organization has reached the 500 GB storage limit
{
  "type": "error",
  "error": {
    "type": "invalid_request_error",
    "message": "File not found: file_011CNha8iCJcU1wXNR6q4V8w"
  }
}

Usage and billing

File API operations are free:

  • Uploading files
  • Downloading files
  • Listing files
  • Getting file metadata
  • Deleting files

File content used in Messages requests are priced as input tokens. You can only download files created by skills or the code execution tool.

Rate limits

During the beta period:

  • File-related API calls are limited to approximately 100 requests per minute
  • Contact us if you need higher limits for your use case