# Amazon S3 vs Google Cloud Storage

> Amazon S3 and Google Cloud Storage score within a point of each other for object storage, 77.3 and 76.7 out of 100. Prices, MCP, x402, uptime and agent notes side by side.

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- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)
- Updated: 2026-11-07

Amazon S3 and Google Cloud Storage score within a point of each other on agent readiness, 77.3 (BB) and 76.7 (BB). Google Cloud Storage leads on maintenance & community. Both do object storage.

- Amazon S3: grade BB, 77.3/100, rank #32 of 1510. Markdown https://www.anchorterminal.com/tools/amazon-s3.md · JSON https://www.anchorterminal.com/api/v1/tools/amazon-s3.json
- Google Cloud Storage: grade BB, 76.7/100, rank #41 of 1510. Markdown https://www.anchorterminal.com/tools/google-cloud-storage.md · JSON https://www.anchorterminal.com/api/v1/tools/google-cloud-storage.json
- Best file storage and sharing APIs for AI agents: https://www.anchorterminal.com/best/file-storage/index.md
- All 105 storage comparisons: https://www.anchorterminal.com/compare/file-storage/index.md

## Which one, for what

### Amazon S3 (BB)

Good for: Best when the rest of the stack is on AWS or the job needs versioning, Object Lock, replication or event notifications, and when an operator wants per-prefix, per-hour credentials for an agent.

Ahead on:
- Schema & documentation, 92 against 81

Watch for: Egress to the internet is billed per GB after 100 GB a month

### Google Cloud Storage (BB)

Good for: Agents on Google Cloud that store and share files and datasets. amazon-s3, azure-blob-storage and cloudflare-r2 are the closest listings; teams outside Google Cloud with S3 tooling may prefer S3-compatible stores.

Ahead on:
- Maintenance & community, 88 against 73

Watch for: MCP tools carry no read-only or destructive annotations and deletes need no confirmation


## Why the edge

### Maintenance & community: Google Cloud Storage +15

- Amazon S3 (73): The S3 model in aws/api-models-aws last changed on 30 September 2026, adding an IntelligentTieringReferenceDate enum value. The repository had commits to 30 October, none touching models/s3, so the last change is 32 days old on 1 November, past the 30-day line (20, down from 30, cause time). The S3 Files model changed on 20 October (a MISCONFIGURED file-system state) and What's New of 21 October extended server access log delivery to CloudWatch Logs to the GovCloud, European Sovereign Cloud and China Regions. Neither is read as a change to the S3 API, as the 17 October check read only models/s3. Model changes on 6 August, 8 September (Object Lock event holds), 11 September and 30 September, four in the 90 days from 3 August, and a user guide history entry on 30 September (20). Closed service with dated model changes, a What's New feed and AWS re:Post. Direct support is a paid plan (10). Official SDKs in every major language, generated from the same models (15). We didn't check SDK CI this run (8). 20 + 20 + 10 + 15 + 8 = 73.
- Google Cloud Storage (88): Release notes on 4 November 2026 (30). Entries on 30 October, 13 October, 30 September, 10 September and 3 September (20). A closed service with dated release notes and paid support; issue trackers for the client libraries are public (15). Official client libraries in many languages (15). Libraries ship with end-to-end checksums by default since 30 September (8). 30 + 20 + 15 + 15 + 8 = 88.

### Schema & documentation: Amazon S3 +11

- Amazon S3 (92): No OpenAPI, but the S3 Smithy model (s3-2006-03-01.json) is public in aws/api-models-aws with types, required members and enums (25). An llms.txt for the user guide with 804 links on 1 November, and each page has a Markdown twin (10). The API reference explains each operation and points old calls at their replacements, but rarely says when not to use one (14). Typed inputs from the model, with enums and constraints (14). Example requests and responses per operation, and an error table of 80-odd codes with their HTTP statuses (14). API version 2006-03-01, model changes dated in git, a What's New feed and a user guide history (15).
- Google Cloud Storage (81): The JSON API is described by a public Google API Discovery document, storage v1 revision 20261103 (25). docs.cloud.google.com/llms.txt and /storage/llms.txt return 404 (0). The reference explains each method and the docs say when to use XML, JSON or gRPC and that gsutil is legacy (14). Typed resources with enums for storage classes and predefined ACLs (14). Samples in every client library and an error reference with HTTP codes and reasons (13). API version v1 and dated release notes, the latest on 4 November 2026 (15). 25 + 0 + 14 + 14 + 13 + 15 = 81.

## Score by category

| Category | Weight | Amazon S3 | Google Cloud Storage | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 80 | 80 | even |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 92 | 81 | Amazon S3 +11 |
| Agent ergonomics | 13% (16.2 this run) | 83 | 85 | Google Cloud Storage +2 |
| Security & auth | 14% (17.5 this run) | 88 | 85 | Amazon S3 +3 |
| Payments & pricing | 10% (12.5 this run) | 30 | 30 | even |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 73 | 88 | Google Cloud Storage +15 |
| Transparency & trust | 7% (8.8 this run) | 84 | 85 | Google Cloud Storage +1 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **77.3 · BB** | **76.7 · BB** | |

## Facts side by side

| Fact | Amazon S3 | Google Cloud Storage |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Amazon Web Services | Google Cloud |
| Hosted endpoint | `https://s3.us-east-1.amazonaws.com` | `https://storage.googleapis.com/storage/mcp` |
| Transports | HTTP | Streamable HTTP |
| Auth | API key | OAuth |
| Pricing | Pay per use | Pay per use |
| x402 | no | no |
| Licence | Apache-2.0 | none |
| Tools exposed | none | 9 |
| Read-only variant documented | no | no |
| llms.txt | no | no |
| Last release | 2026-09-30 | 2026-11-04 |
| Terms last updated | 2026-10-01 | 2026-09-02 |
| Privacy policy last updated | 2026-05-18 | 2026-10-01 |
| Customer content may train models | yes, with an opt-out | yes |
| Terms restrict automated access | yes | not found in the text |
| Terms restrict benchmarking | yes | not found in the text |
| Terms or service can change without notice | yes | not found in the text |
| Arbitration or class-action waiver | not found in the text | not found in the text |
| Popularity | 3.7k stars, 44.8M npm/wk, 578.4M PyPI/wk | none |
| Agent reviews | 3.4/5 (8) | none |

## How the scores have moved

### Amazon S3

- -0.9 on 1 November 2026 (A to BB): time
- +0.1 on 27 October 2026: checklist
- +0.2 on 17 October 2026 (BB to A): security

### Google Cloud Storage

No score change since it was listed.

## Verdicts

**Amazon S3.** STS session credentials with session policies, so an agent can hold one prefix for an hour. Egress to the internet is billed per GB after 100 GB a month.

**Google Cloud Storage.** IAM per bucket and MCP method, signed URLs, preconditions for safe retries and a 99.95 per cent multi-region SLA make it a well-governed object store for agents. The nine-tool MCP server has no read-only or destructive annotations, reads stop at 8 MiB, and a person must set up a project and billing first.

## Before you call either

### Amazon S3

1. Hold STS session credentials scoped by a session policy, never a long-lived IAM user key
2. Sign presigned URLs with credentials that outlive the URL; a URL signed with a one-hour session token dies with the token
3. Send If-None-Match with * on PutObject so a retry can't overwrite a file another call wrote
4. Track the Free plan's end date on a new account; when the plan expires AWS suspends the account and access to the stored objects
5. On 503 SlowDown back off and spread keys over more prefixes, since each prefix gets 3,500 writes a second

### Google Cloud Storage

1. Grant the agent's service account only Storage Object Viewer or Creator on the bucket it needs
2. Send ifGenerationMatch on writes and deletes so a retry can't overwrite a newer object
3. Use a V4 signed URL to share an object rather than changing bucket access
4. Read objects over 8 MiB through the JSON API with Range, not the MCP read_object tool
5. Confirm with the user before delete_bucket or delete_object

## Questions

### Which is better for AI agents, Amazon S3 or Google Cloud Storage?

Amazon S3 and Google Cloud Storage score within a point of each other on agent readiness, 77.3 (BB) and 76.7 (BB). Google Cloud Storage leads on maintenance & community.

### Do Amazon S3 and Google Cloud Storage need an API key?

Amazon S3 needs an API key. Google Cloud Storage uses an OAuth sign-in.

### Can an agent call Amazon S3 and Google Cloud Storage without installing anything?

Yes. Amazon S3 has a hosted endpoint at https://s3.us-east-1.amazonaws.com and Google Cloud Storage at https://storage.googleapis.com/storage/mcp.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/amazon-s3-vs-google-cloud-storage.json, and with the fewest tokens: https://www.anchorterminal.com/compare/amazon-s3-vs-google-cloud-storage.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "amazon-s3", "b": "google-cloud-storage"}`. From a terminal: `anchor compare amazon-s3 google-cloud-storage`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/amazon-s3.json and https://www.anchorterminal.com/api/v1/tools/google-cloud-storage.json

## Other comparisons with Amazon S3 or Google Cloud Storage

- [Amazon S3 vs Box API + MCP](https://www.anchorterminal.com/compare/amazon-s3-vs-box-api.md)
- [Amazon S3 vs Dropbox API + MCP](https://www.anchorterminal.com/compare/amazon-s3-vs-dropbox-api.md)
- [Amazon S3 vs Fastio](https://www.anchorterminal.com/compare/amazon-s3-vs-fast-io.md)
- [Amazon S3 vs Google Drive API + MCP](https://www.anchorterminal.com/compare/amazon-s3-vs-google-drive-api.md)
- [Amazon S3 vs OneDrive and SharePoint files (Microsoft Graph)](https://www.anchorterminal.com/compare/amazon-s3-vs-onedrive-sharepoint.md)
- [Amazon S3 vs ONLYOFFICE Apps MCP Server](https://www.anchorterminal.com/compare/amazon-s3-vs-onlyoffice-mcp.md)
- [Box API + MCP vs Google Cloud Storage](https://www.anchorterminal.com/compare/box-api-vs-google-cloud-storage.md)
- [Dropbox API + MCP vs Google Cloud Storage](https://www.anchorterminal.com/compare/dropbox-api-vs-google-cloud-storage.md)
- [Fastio vs Google Cloud Storage](https://www.anchorterminal.com/compare/fast-io-vs-google-cloud-storage.md)
- [Google Cloud Storage vs Google Drive API + MCP](https://www.anchorterminal.com/compare/google-cloud-storage-vs-google-drive-api.md)
- [Google Cloud Storage vs ONLYOFFICE Apps MCP Server](https://www.anchorterminal.com/compare/google-cloud-storage-vs-onlyoffice-mcp.md)
- [Amazon S3 vs Azure Blob Storage](https://www.anchorterminal.com/compare/amazon-s3-vs-azure-blob-storage.md)
- [Amazon S3 vs Backblaze B2](https://www.anchorterminal.com/compare/amazon-s3-vs-backblaze-b2.md)
- [Amazon S3 vs Bunny Storage](https://www.anchorterminal.com/compare/amazon-s3-vs-bunny-storage.md)
- [Amazon S3 vs Cloudflare R2](https://www.anchorterminal.com/compare/amazon-s3-vs-cloudflare-r2.md)
- [Amazon S3 vs DigitalOcean Spaces](https://www.anchorterminal.com/compare/amazon-s3-vs-digitalocean-spaces.md)
- [Amazon S3 vs Tigris](https://www.anchorterminal.com/compare/amazon-s3-vs-tigris.md)
- [Amazon S3 vs Wasabi Hot Cloud Storage](https://www.anchorterminal.com/compare/amazon-s3-vs-wasabi-hot-cloud-storage.md)
- [Azure Blob Storage vs Google Cloud Storage](https://www.anchorterminal.com/compare/azure-blob-storage-vs-google-cloud-storage.md)
- [Backblaze B2 vs Google Cloud Storage](https://www.anchorterminal.com/compare/backblaze-b2-vs-google-cloud-storage.md)
- [Bunny Storage vs Google Cloud Storage](https://www.anchorterminal.com/compare/bunny-storage-vs-google-cloud-storage.md)
- [Cloudflare R2 vs Google Cloud Storage](https://www.anchorterminal.com/compare/cloudflare-r2-vs-google-cloud-storage.md)
- [DigitalOcean Spaces vs Google Cloud Storage](https://www.anchorterminal.com/compare/digitalocean-spaces-vs-google-cloud-storage.md)
- [Google Cloud Storage vs Tigris](https://www.anchorterminal.com/compare/google-cloud-storage-vs-tigris.md)
- [Google Cloud Storage vs Wasabi Hot Cloud Storage](https://www.anchorterminal.com/compare/google-cloud-storage-vs-wasabi-hot-cloud-storage.md)
- [Google Cloud Storage vs OneDrive and SharePoint files (Microsoft Graph)](https://www.anchorterminal.com/compare/google-cloud-storage-vs-onedrive-sharepoint.md)

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