Cloud Storage Comparison: 10 Major Services | Upload Limits, Pricing & Features | S3/GCS/Azure/R2

When choosing a cloud storage service, key comparison points include single upload limits, multipart upload support, free tier, pricing, and egress (transfer) costs. While AWS S3 is the de facto industry standard, there are more suitable options depending on cost, edge delivery, and specific use cases. This article compares the specifications of 10 major services and provides recommendations by use case.

Comparison table of single upload limit, multipart limit, and free tier

※Pricing is an estimate as of April 2026. Prices vary by region, storage class, and usage. Most egress (data transfer) costs are not included in the table above.

Features and selection guide for each service

AWS S3

The de facto standard for cloud storage. Many services implement S3-compatible APIs, and the ecosystem of libraries and tools is the most mature. Multipart uploads can be automated with <code>aws-sdk</code>, supporting a minimum chunk size of 5MB and up to 10,000 parts to upload objects up to 5TB. Integration with CloudFront enables easy edge delivery. However, egress costs are high (from $0.09/GB), which can be a challenge for services with large data transfers.

Google Cloud Storage（GCS）

With a generous single object limit of 5TB, it is well-suited for use cases where you want to manage large files as single objects. Its strength lies in seamless integration with GCP services such as BigQuery and Vertex AI, making it the first choice for building data analysis pipelines. Transfer costs tend to be slightly lower than S3.

Azure Blob Storage

It integrates seamlessly with the Microsoft ecosystem (Office 365, Active Directory, Azure Functions, etc.) and offers comprehensive authentication and compliance features for enterprise use. Block Blobs support objects up to 4.75TB, while Page Blobs (for virtual disks) support up to 8TB. Cost optimization is achievable through hot, cool, and archive tiers.

Cloudflare R2

The main feature is that egress costs are free. Since it uses S3-compatible API, you can use existing S3 clients almost as-is. Integration with Workers (edge computing) is powerful, enabling architectures that directly manipulate storage at the edge. It offers a permanent free tier of 10GB/month, making it ideal for personal development and small-scale services.

Backblaze B2

Offers industry-leading lowest-tier pricing ($0.006/GB/month), well-suited for cost-conscious backup and media archive use cases. The combination with Cloudflare's "Bandwidth Alliance" where B2 egress to Cloudflare is free is popular. It provides S3-compatible APIs, making migration easy.

DigitalOcean Spaces

Features a flat-rate plan starting from $5/month that includes 250GB storage and 1TB transfer bandwidth. Its advantage is easy budget predictability for small-scale services. CDN comes standard and is simple to configure. Transfer becomes free when used in the same region as DigitalOcean Droplets (virtual machines).

Wasabi

S3-compatible with free egress (when downloading directly from Wasabi), and affordable storage ($0.0068/GB/month). However, note the minimum retention period: data deleted within 90 days of storage incurs 90 days of charges. It's suitable for backups and long-term cold data storage.

MinIO

Open-source S3-compatible object storage that can be self-hosted on-premises or in private clouds. It has excellent compatibility with Kubernetes and official Helm charts are provided. It is used in regulated industries that prefer not to move data to the cloud, as well as for development and testing in on-premises environments.

Firebase Storage

It uses GCS internally, and direct uploads from mobile/web apps using the Firebase SDK can be easily implemented. Its strength is fine-grained access control (Security Rules) integrated with Firebase Authentication. However, on the Spark (free) plan, the single file size limit may be effectively set low.

Supabase Storage

Storage functionality of Supabase, a PostgreSQL-based BaaS (Backend as a Service). Its unique strength is access control based on RLS (Row Level Security) with Supabase Auth. The Free plan has a low file size limit of 50MB, so Pro or higher plans (50GB per file) are required for large files.

Recommendations by use case

What is Multipart Upload

Multipart upload is a mechanism that divides large files into smaller parts and uploads them in parallel. It is recommended for files exceeding 100MB on S3 and mandatory for files exceeding 5GB. The main benefits are as follows.

• Improved throughput with parallel uploads
• Only failed parts can be retransmitted during network interruption (resumable)
• Bypass the 5GB limit of single requests and send up to 5TB

// AWS SDK v3 でのマルチパートアップロード例
import { S3Client, CreateMultipartUploadCommand,
         UploadPartCommand, CompleteMultipartUploadCommand } from '@aws-sdk/client-s3';

const s3 = new S3Client({ region: 'ap-northeast-1' });

async function multipartUpload(bucket, key, file) {
    // アップロードの開始
    const { UploadId } = await s3.send(new CreateMultipartUploadCommand({
        Bucket: bucket, Key: key,
    }));

    const chunkSize = 10 * 1024 * 1024; // 10MB
    const parts = [];

    for (let i = 0; i * chunkSize < file.size; i++) {
        const chunk = file.slice(i * chunkSize, (i + 1) * chunkSize);
        const { ETag } = await s3.send(new UploadPartCommand({
            Bucket: bucket, Key: key,
            UploadId, PartNumber: i + 1,
            Body: chunk,
        }));
        parts.push({ ETag, PartNumber: i + 1 });
    }

    // パーツの結合（完了）
    await s3.send(new CompleteMultipartUploadCommand({
        Bucket: bucket, Key: key,
        UploadId, MultipartUpload: { Parts: parts },
    }));
}