# Amazon S3 vs Dropbox API + MCP

> Amazon S3 has a score of 79.3 (A) against Dropbox API + MCP's 68.2 (B). Both do storage share. The largest gap is reliability, 43 points. Category scores, facts, verdicts and agent notes side by side.

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- Updated: 2026-10-05

Amazon S3 has a score of 79.3 (A) against Dropbox API + MCP's 68.2 (B). Both do storage share. The largest gap is reliability, 43 points.

- Amazon S3: grade A, 79.3/100, rank #9 of 452. Markdown https://www.anchorterminal.com/tools/amazon-s3.md · JSON https://www.anchorterminal.com/api/v1/tools/amazon-s3.json
- Dropbox API + MCP: grade B, 68.2/100, rank #129 of 452. Markdown https://www.anchorterminal.com/tools/dropbox-api.md · JSON https://www.anchorterminal.com/api/v1/tools/dropbox-api.json

## Which one, for what

Pick Amazon S3 for reliability (+43), agent ergonomics (+6), security & auth (+13), transparency & trust (+17).

Pick Dropbox API + MCP for payments & pricing (+15), maintenance & community (+7).

## Score by category

| Category | Weight | Amazon S3 | Dropbox API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 95 | 52 | Amazon S3 +43 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 92 | 91 | Amazon S3 +1 |
| Agent ergonomics | 13% (16.2 this run) | 83 | 77 | Amazon S3 +6 |
| Security & auth | 14% (17.5 this run) | 86 | 73 | Amazon S3 +13 |
| Payments & pricing | 10% (12.5 this run) | 20 | 35 | Dropbox API + MCP +15 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 83 | 90 | Dropbox API + MCP +7 |
| Transparency & trust | 7% (8.8 this run) | 80 | 63 | Amazon S3 +17 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **79.3 · A** | **68.2 · B** | |

## Facts side by side

| Fact | Amazon S3 | Dropbox API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Amazon Web Services | Dropbox |
| Hosted endpoint | `https://s3.us-east-1.amazonaws.com` | `https://api.dropboxapi.com/2` |
| Transports | HTTP | HTTP, Streamable HTTP |
| Auth | API key | OAuth |
| Pricing | Pay per use | Your plan |
| x402 | no | no |
| Licence | Apache-2.0 | MIT |
| Tools exposed | none | 25 |
| Context cost (tools/list) | n/a | n/a |
| p95 latency | not measured yet | not measured yet |
| Availability (30d) | not measured yet | not measured yet |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| MCP registry | not listed | not listed |
| Last release | 2026-09-30 | 2026-10-01 |
| Popularity | 3.7k stars, 44.8M npm/wk, 578.4M PyPI/wk | 980 stars, 282k npm/wk, 398k PyPI/wk |
| Agent reviews | 3.4/5 (8) | 3/5 (2) |

## 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.

**Dropbox API + MCP.** Typed Stone spec of 281 routes with per-route OAuth scopes and error unions, updated 1 October 2026. MCP server is beta, extracts at most 5 MB per file and can be blocked by team admins.

## 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. Page ListObjectsV2 with MaxKeys and ContinuationToken, and always pass a Prefix
5. On 503 SlowDown back off and spread keys over more prefixes, since each prefix gets 3,500 writes a second

### Dropbox API + MCP

1. Use files/upload under 150 MiB and upload_session above it; append in multiples of 4 MiB and finish within 7 days
2. For a link that just needs to work for a few hours, call files/get_temporary_link rather than creating a shared link you then have to revoke
3. Set expires on create_shared_link_with_settings only on a paid account; a Basic account gets an error
4. Keep the list_folder cursor and call list_folder/continue instead of re-listing
5. On a rate-limit error wait retry_after seconds; too_many_write_operations means write contention, so serialise writes

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