Object storage

Object storage services keep files of any size, such as backups, media, datasets, logs and website assets, in buckets you reach over an HTTP API, most often the Amazon S3 API or one compatible with it. Engineering and IT teams use them for backups and archives, for serving downloads and media, for data lakes, and as the storage behind their own applications. They differ less in what they store than in how they bill: per GB or per TB, with or without request fees, with egress metered per GB, free up to a share of what you store, or not charged at all, and with or without minimum charges, durations and object sizes. They also differ in how fully they implement the S3 API and its data protection features, and in the compliance papers they offer.

We compare them on the same six indicators, read from each vendor's pricing, docs, security and legal pages:

• Pricing clarity: whether storage, request and egress prices are published and can be bought online, and whether the pages leave prices out or contradict themselves.
• Free tier: permanent free storage, and whether requests and downloads are free on it; otherwise a trial or credit.
• Price for 1 TB a month: the lowest list cost to store 1 TB in the standard class in a US region, download 1 TB of it and make 1 million writes and 10 million reads a month, with the arithmetic shown; 0 when the pages cannot price it.
• Egress and billing rules: whether downloads are billed, and any minimum storage duration, minimum object size or minimum monthly charge.
• S3 API and data protection: an S3 or S3-compatible API, versioning, a retention lock no one can remove, lifecycle rules, built-in replication and keys you manage.
• Compliance, regions and access: the vendor's own SOC 2 Type II, ISO 27001, a HIPAA BAA, console SSO, bucket-scoped keys, an audit log, and the choice of regions, including the EU.

Durability figures, availability SLAs and transfer speed are vendor statements we do not score or publish. Each review says which pages it was written from and when. Where we have run a product hands-on, the evidence is on its page.