--- title: UploadPart · S3 API description: Uploads one part of a multipart upload. doc_version: 0.1.0-preview last_updated: 2026-09-14 --- # UploadPart `PUT /{bucket}/{key}?partNumber&uploadId` Uploads one part of a multipart upload. Send the parts in any order, or at the same time. A part with a part number that exists replaces it. Keep the ETag of each part for CompleteMultipartUpload. - Role: Editor or higher. - Support: supported. - Auth: AWS Signature Version 4 with your API key. See [S3 API](/api/s3.md). - Returns the part ETag. Every part except the last must be the same size. ## Example request ```http PUT /support-tickets/big.bin?partNumber=1&uploadId=VXBsb2FkIGZvciBiaWcuYmlu HTTP/1.1 Host: wspq7ws2np5l8z4.storage.beta.graphon.sh x-amz-date: 20261007T093000Z x-amz-content-sha256: UNSIGNED-PAYLOAD Authorization: AWS4-HMAC-SHA256 Credential=/20261007/us-east-1/s3/aws4_request, SignedHeaders=host;x-amz-content-sha256;x-amz-date, Signature= Content-Length: 104857600 <104857600 bytes> ``` ## Path parameters - `bucket` (string, required): The bucket name. - `key` (string, required): The object key. Keep each `/` as it is. Percent-encode the other reserved characters. ## Query parameters - `partNumber` (integer, required): The part number, from 1 through 10,000. - `uploadId` (string, required): The upload ID from CreateMultipartUpload. ## Headers - `Content-Length` (integer, required): The size of the body in bytes. One request can carry at most 200 MiB. - `Content-MD5` (string, optional): The base64 MD5 digest of the body. A different digest returns `400 BadDigest`. - `x-amz-checksum-*` (string, optional): A base64 checksum of the part: `crc32`, `crc32c`, `crc64nvme`, `sha1`, or `sha256`. Storage checks it. A different checksum returns `400 BadDigest`. - `x-amz-sdk-checksum-algorithm` (string, optional): The checksum to compute: `CRC32`, `CRC32C`, `CRC64NVME`, `SHA1`, or `SHA256`. `x-amz-checksum-algorithm` does the same. - `x-amz-expected-bucket-owner` (string, optional): The workspace ID that must own the bucket. Another owner returns `403 AccessDenied`. ## Request body - `Body` (binary, required): The bytes of the part. ## Responses ### 200 · OK Storage stored the part. Response headers: - `ETag` (string, optional): The entity tag of the part. Send it to CompleteMultipartUpload. ```http HTTP/1.1 200 OK ETag: "7ac66c0f148de9519b8bd264312c4d64" x-amz-request-id: 4F8A2C7D1E6B4093A5C2D8E1F7B3A960 ``` ## Errors Any request can also get the common errors on [S3 API](/api/s3.md). ### 404 · `NoSuchUpload` The upload ID is not known for this key. The upload was completed or aborted. Start a new upload with CreateMultipartUpload. ### 400 · `InvalidArgument` The partNumber is not an integer from 1 through 10,000. Number the parts from 1 through 10,000. ### 400 · `BadDigest` A checksum header does not match the body. Storage did not keep the bytes. Compute the checksum from the bytes that you send, then send the request again. ### 400 · `XAmzContentSHA256Mismatch` The body does not match the SHA-256 that the request signed. Hash the bytes that you send, then sign and send the request again. ### 400 · `IncompleteBody` The body ended before the length that the request declared. Send the whole body again. ### 411 · `MissingContentLength` An `aws-chunked` body came without `x-amz-decoded-content-length`. Send the object size in `x-amz-decoded-content-length`. ### 413 · `EntityTooLarge` The body is larger than 200 MiB. Use a multipart upload. The aws CLI and the SDKs do this for a large file by themselves. ### 503 · `SlowDown` The bucket has too many writes in progress. The response has `Retry-After: 1`. Wait for the Retry-After time, then send the request again. SDKs retry by themselves. ### 404 · `NoSuchBucket` No bucket has this name, or the bucket was deleted. Check the bucket name. ListBuckets shows the buckets of the workspace. ### 403 · `AccessDenied` The key does not have the role for this operation, or the bucket is in another workspace. Use a key of the workspace that owns the bucket, with the role above. ## Other request languages ### aws CLI ```bash # The graphon profile from the S3 API overview. export AWS_PROFILE=graphon UPLOAD_ID="VXBsb2FkIGZvciBiaWcuYmlu" # The UploadId from create-multipart-upload aws s3api upload-part \ --bucket support-tickets \ --key big.bin \ --part-number 1 \ --upload-id "$UPLOAD_ID" \ --body part-1.bin ``` ### Python (boto3) ```python # Replace wspq7ws2np5l8z4 with your workspace ID. import os import boto3 from botocore.config import Config api_key = os.environ["GRAPHON_API_KEY"] access_key_id = api_key.split("_", 1)[1].split(".")[0] s3 = boto3.client( "s3", endpoint_url="https://wspq7ws2np5l8z4.storage.beta.graphon.sh", region_name="us-east-1", aws_access_key_id=access_key_id, aws_secret_access_key=api_key, config=Config(signature_version="s3v4", s3={"addressing_style": "path"}), ) upload_id = "VXBsb2FkIGZvciBiaWcuYmlu" # The UploadId from create_multipart_upload response = s3.upload_part( Bucket="support-tickets", Key="big.bin", PartNumber=1, UploadId=upload_id, Body=open("part-1.bin", "rb"), ) print(response["ETag"]) ``` ### JavaScript (AWS SDK) ```javascript // Replace wspq7ws2np5l8z4 with your workspace ID. import { S3Client, UploadPartCommand } from '@aws-sdk/client-s3'; import { createReadStream } from 'node:fs'; const apiKey = process.env.GRAPHON_API_KEY; if (!apiKey) throw new Error('Set GRAPHON_API_KEY.'); const accessKeyId = apiKey.split('_')[1].split('.')[0]; const s3 = new S3Client({ endpoint: 'https://wspq7ws2np5l8z4.storage.beta.graphon.sh', region: 'us-east-1', forcePathStyle: true, credentials: { accessKeyId, secretAccessKey: apiKey }, }); const uploadId = 'VXBsb2FkIGZvciBiaWcuYmlu'; // The UploadId from CreateMultipartUpload const response = await s3.send(new UploadPartCommand({ Bucket: 'support-tickets', Key: 'big.bin', PartNumber: 1, UploadId: uploadId, Body: createReadStream('part-1.bin'), })); console.log(response.ETag); ``` ## Sitemap See the full [sitemap](/sitemap.md) for all pages.