S3 vs GCS vs Azure Blob

Amazon S3, Google Cloud Storage, and Azure Blob Storage are the object storage services of the three major cloud providers. All offer 11 nines of durability, multiple storage tiers, and global availability. The differences lie in pricing, ecosystem integration, and feature details.

Storage Tiers

All three providers offer hot, warm, cold, and archive tiers. S3's tiers are Standard, Infrequent Access, One Zone-IA, Glacier Instant Retrieval, Glacier Flexible Retrieval, and Glacier Deep Archive. GCS offers Standard, Nearline (30-day minimum), Coldline (90-day), and Archive (365-day). Azure has Hot, Cool, Cold, and Archive.

S3 Glacier Deep Archive and Azure Archive offer the lowest cold storage prices (under $0.002/GB/month), making them ideal for compliance and backup data that is rarely accessed.

Pricing Nuances

Storage pricing is similar across providers, with GCS slightly cheaper for standard storage. The real cost differences appear in egress (data transfer out) and API request pricing. S3 egress starts at $0.09/GB, GCS at $0.12/GB, and Azure at $0.087/GB. For egress-heavy workloads, these differences compound.

All three offer free intra-region transfer and cheaper inter-region transfer. Consider your data access patterns carefully when estimating costs.

Ecosystem Integration

S3 is the de facto standard for object storage APIs. Many third-party tools, databases, and analytics platforms support the S3 API natively. GCS offers an S3-compatible XML API for migration ease. Each service integrates deeply with its own cloud's analytics stack: S3 with Athena and Redshift, GCS with BigQuery, and Azure Blob with Synapse Analytics.

For storage architecture patterns, explore our concepts and system design interview guide. Practice with interview questions and check pricing.