Upload part of file

cURL

curl -i -X PUT "https://upload.box.com/api/2.0/files/upload_sessions/F971964745A5CD0C001BBE4E58196BFD" \
     -H "authorization: Bearer <ACCESS_TOKEN>" \
     -H "digest: sha=fpRyg5eVQletdZqEKaFlqwBXJzM=" \
     -H "content-range: bytes 8388608-16777215/445856194" \
     -H "content-type: application/octet-stream" \
     --data-binary @<FILE_NAME>

await client.chunkedUploads.uploadFilePart(
  acc.uploadSessionId,
  generateByteStreamFromBuffer(chunkBuffer),
  {
    digest: digest,
    contentRange: contentRange,
  } satisfies UploadFilePartHeadersInput,
);

try await client.chunkedUploads.uploadFilePart(uploadSessionId: acc.uploadSessionId, requestBody: Utils.generateByteStreamFromBuffer(buffer: chunkBuffer), headers: UploadFilePartHeaders(digest: digest, contentRange: contentRange))

await client.ChunkedUploads.UploadFilePartAsync(uploadSessionId: acc.UploadSessionId, requestBody: Utils.GenerateByteStreamFromBuffer(buffer: chunkBuffer), headers: new UploadFilePartHeaders(digest: digest, contentRange: contentRange));

{
  "part": {
    "part_id": "6F2D3486",
    "offset": 16777216,
    "size": 3222784,
    "sha1": "134b65991ed521fcfe4724b7d814ab8ded5185dc",
    "sha512": "ae78a0ca28abffe70ac9aba830556cd6eb3fcf1501dbd9b2d7a5f45992c00812cb07b51bbd0a9174e2295671c0e86f30354afa91d281d4fbee6a323a483d6383"
  }
}

{
  "type": "error",
  "status": 400,
  "code": "item_name_invalid",
  "message": "Method Not Allowed",
  "context_info": {
    "message": "Something went wrong"
  },
  "help_url": "https://developer.box.com/guides/api-calls/permissions-and-errors/common-errors/",
  "request_id": "abcdef123456"
}

{
  "type": "error",
  "status": 400,
  "code": "item_name_invalid",
  "message": "Method Not Allowed",
  "context_info": {
    "message": "Something went wrong"
  },
  "help_url": "https://developer.box.com/guides/api-calls/permissions-and-errors/common-errors/",
  "request_id": "abcdef123456"
}

{
  "type": "error",
  "status": 400,
  "code": "item_name_invalid",
  "message": "Method Not Allowed",
  "context_info": {
    "message": "Something went wrong"
  },
  "help_url": "https://developer.box.com/guides/api-calls/permissions-and-errors/common-errors/",
  "request_id": "abcdef123456"
}

{
  "type": "error",
  "status": 400,
  "code": "item_name_invalid",
  "message": "Method Not Allowed",
  "context_info": {
    "message": "Something went wrong"
  },
  "help_url": "https://developer.box.com/guides/api-calls/permissions-and-errors/common-errors/",
  "request_id": "abcdef123456"
}

PUT

files

upload_sessions

{upload_session_id}

cURL

curl -i -X PUT "https://upload.box.com/api/2.0/files/upload_sessions/F971964745A5CD0C001BBE4E58196BFD" \
     -H "authorization: Bearer <ACCESS_TOKEN>" \
     -H "digest: sha=fpRyg5eVQletdZqEKaFlqwBXJzM=" \
     -H "content-range: bytes 8388608-16777215/445856194" \
     -H "content-type: application/octet-stream" \
     --data-binary @<FILE_NAME>

await client.chunkedUploads.uploadFilePart(
  acc.uploadSessionId,
  generateByteStreamFromBuffer(chunkBuffer),
  {
    digest: digest,
    contentRange: contentRange,
  } satisfies UploadFilePartHeadersInput,
);

try await client.chunkedUploads.uploadFilePart(uploadSessionId: acc.uploadSessionId, requestBody: Utils.generateByteStreamFromBuffer(buffer: chunkBuffer), headers: UploadFilePartHeaders(digest: digest, contentRange: contentRange))

await client.ChunkedUploads.UploadFilePartAsync(uploadSessionId: acc.UploadSessionId, requestBody: Utils.GenerateByteStreamFromBuffer(buffer: chunkBuffer), headers: new UploadFilePartHeaders(digest: digest, contentRange: contentRange));

{
  "part": {
    "part_id": "6F2D3486",
    "offset": 16777216,
    "size": 3222784,
    "sha1": "134b65991ed521fcfe4724b7d814ab8ded5185dc",
    "sha512": "ae78a0ca28abffe70ac9aba830556cd6eb3fcf1501dbd9b2d7a5f45992c00812cb07b51bbd0a9174e2295671c0e86f30354afa91d281d4fbee6a323a483d6383"
  }
}

{
  "type": "error",
  "status": 400,
  "code": "item_name_invalid",
  "message": "Method Not Allowed",
  "context_info": {
    "message": "Something went wrong"
  },
  "help_url": "https://developer.box.com/guides/api-calls/permissions-and-errors/common-errors/",
  "request_id": "abcdef123456"
}

{
  "type": "error",
  "status": 400,
  "code": "item_name_invalid",
  "message": "Method Not Allowed",
  "context_info": {
    "message": "Something went wrong"
  },
  "help_url": "https://developer.box.com/guides/api-calls/permissions-and-errors/common-errors/",
  "request_id": "abcdef123456"
}

{
  "type": "error",
  "status": 400,
  "code": "item_name_invalid",
  "message": "Method Not Allowed",
  "context_info": {
    "message": "Something went wrong"
  },
  "help_url": "https://developer.box.com/guides/api-calls/permissions-and-errors/common-errors/",
  "request_id": "abcdef123456"
}

{
  "type": "error",
  "status": 400,
  "code": "item_name_invalid",
  "message": "Method Not Allowed",
  "context_info": {
    "message": "Something went wrong"
  },
  "help_url": "https://developer.box.com/guides/api-calls/permissions-and-errors/common-errors/",
  "request_id": "abcdef123456"
}

This endpoint is in the version 2024.0. No changes are required to continue using it. For more details, see Box API versioning.Learn more about Box SDK versioning strategy.

Authorizations

Authorization

string

header

required

The access token received from the authorization server in the OAuth 2.0 flow.

Headers

digest

string

required

The RFC3230 message digest of the chunk uploaded.

SHA-1 and SHA-512 (RFC5843) are supported. The digest must be base64 encoded. The format of this header is as sha=BASE64_ENCODED_DIGEST for SHA-1, or sha-512=BASE64_ENCODED_DIGEST for SHA-512.

To get the value for the digest, use the openSSL command to encode the file part: openssl sha1 -binary <FILE_PART_NAME> | base64 for SHA-1, or openssl sha512 -binary <FILE_PART_NAME> | base64 for SHA-512.

content-range

string

required

The byte range of the chunk.

Must not overlap with the range of a part already uploaded this session. Each part’s size must be exactly equal in size to the part size specified in the upload session that you created. One exception is the last part of the file, as this can be smaller.

When providing the value for content-range, remember that:

The lower bound of each part's byte range must be a multiple of the part size.
The higher bound must be a multiple of the part size - 1.

Path Parameters

upload_session_id

string

required

The ID of the upload session.

Body

application/octet-stream

The binary content of the file.

Response

Chunk has been uploaded successfully.

The response always includes sha512. It also includes sha1 if the Digest header used SHA-1.

A chunk of a file uploaded as part of an upload session, as returned by some endpoints.

part

Upload part · object

The representation of an upload session chunk.

Show child attributes

Last modified on January 23, 2026

API reference

v2025.0

v2026.0

Authorizations

Headers

Path Parameters

Body

Response