Multipart Upload

Multipart Upload allows for the upload of large objects in parts. This provides improved throughput and greater resilience to network errors. You can upload parts in parallel to improve throughput, or if an upload of a part fails, you can re-upload that part without affecting other parts.

Tigris is S3-compatible, so you can use the same SDKs and patterns for multipart uploads. Tigris also routes traffic to the nearest region by default via its global endpoint, providing accelerated, low-latency ingress without any extra configuration. Use https://t3.storage.dev.

Prerequisites

• A Tigris account and access keys.
• A bucket.
• An SDK that supports S3 Multipart Upload.

Tigris implements the standard S3 Multipart Upload operations (CreateMultipartUpload, UploadPart, CompleteMultipartUpload, etc.), so any modern S3 client will work.

When using an S3-compatible tool or SDK, you should use the global endpoint https://t3.storage.dev and virtual-hosted style addressing, where the bucket is in the hostname.

Example: Node.js (AWS SDK v3) — Managed Multipart Upload

The following is an example of a managed multipart upload using the AWS SDK v3 for Node.js.

import { S3Client } from "@aws-sdk/client-s3";
import { Upload } from "@aws-sdk/lib-storage";
import { createReadStream } from "node:fs";

const s3 = new S3Client({
  region: "auto",
  endpoint: "https://t3.storage.dev",
  s3ForcePathStyle: false, // virtual-hosted-style
  credentials: {
    accessKeyId: process.env.AWS_ACCESS_KEY_ID!,
    secretAccessKey: process.env.AWS_SECRET_ACCESS_KEY!,
  },
});

export async function putLargeObject(
  bucket: string,
  key: string,
  filePath: string,
) {
  const upload = new Upload({
    client: s3,
    params: { Bucket: bucket, Key: key, Body: createReadStream(filePath) },
    queueSize: 8, // concurrency
    partSize: 32 * 1024 * 1024, // 32 MiB parts
  });
  await upload.done();
}

Example: Python (boto3) — Tuned Transfer Config

The following is an example of a multipart upload with a tuned transfer configuration using boto3 for Python.

import boto3
from botocore.config import Config
from boto3.s3.transfer import TransferConfig

s3 = boto3.client(
    "s3",
    endpoint_url="https://t3.storage.dev",
    aws_access_key_id=os.environ["AWS_ACCESS_KEY_ID"],
    aws_secret_access_key=os.environ["AWS_SECRET_ACCESS_KEY"],
    config=Config(s3={"addressing_style": "virtual"})
)

# 32 MiB parts, multipart threshold 64 MiB
tconfig = TransferConfig(
    multipart_threshold=64 * 1024 * 1024,
    multipart_chunksize=32 * 1024 * 1024,
    max_concurrency=8,
    use_threads=True
)

def put_large_object(bucket, key, path):
    s3.upload_file(path, bucket, key, Config=tconfig)

The upload_file method will transparently switch to a multipart upload for files larger than the specified threshold.

Cleaning Up In-Progress Uploads

It is good practice to occasionally list and abort stale multipart uploads to reclaim storage.

• ListMultipartUploads to discover in-progress multipart uploads
• AbortMultipartUpload to cancel stale multipart uploads

Each SDK exposes these as standard S3 operations.

Browser & Mobile Uploads

For browser and mobile applications, it is recommended to not proxy large payloads through your servers. Two common approaches are:

• Presigned URLs: Generate a time-limited URL on your server and upload directly from the browser or mobile app.
• HTML Form POST: Use a policy-based POST from the browser to constrain headers like Content-Type and object key patterns.

CLI & Tools

The following tools can be used for multipart uploads.

• AWS CLI:

  aws s3 cp bigfile.bin s3://my-bucket/bigfile.bin \
    --endpoint-url https://t3.storage.dev

  The AWS CLI automatically switches to multipart for large files.

• rclone: Set the endpoint to https://t3.storage.dev.

Limits

• Standard S3 multipart semantics apply (e.g., large objects up to 5 TB).
• Tigris implements the S3 MPU API surface (create/upload parts/complete/list/abort).