# Backblaze B2 vs Fastio

> Backblaze B2 scores 75.3 (BB) to Fastio's 55.2 (C) for file sharing. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/backblaze-b2-vs-fast-io
- Markdown: https://www.anchorterminal.com/compare/backblaze-b2-vs-fast-io.md (~2,400 tokens)
- Slim: https://www.anchorterminal.com/compare/backblaze-b2-vs-fast-io.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/backblaze-b2-vs-fast-io.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-09

Backblaze B2 scores 75.3 (BB) on agent readiness against Fastio's 55.2 (C), and leads in every scored category. Both do file sharing.

- Backblaze B2: grade BB, 75.3/100, rank #49 of 950. Markdown https://www.anchorterminal.com/tools/backblaze-b2.md · JSON https://www.anchorterminal.com/api/v1/tools/backblaze-b2.json
- Fastio: grade C, 55.2/100, rank #663 of 950. Markdown https://www.anchorterminal.com/tools/fast-io.md · JSON https://www.anchorterminal.com/api/v1/tools/fast-io.json
- Best file storage and sharing APIs for AI agents: https://www.anchorterminal.com/best/file-storage/index.md
- All 75 storage comparisons: https://www.anchorterminal.com/compare/file-storage/index.md

## Which one, for what

### Backblaze B2 (BB)

Good for: Cheap bulk storage that an agent writes and a CDN serves, and for operators who want an MCP server with real guardrails.

Ahead on:
- Reliability, 60 against 33
- Schema & documentation, 89 against 65
- Agent ergonomics, 85 against 73
- Security & auth, 90 against 74
- Payments & pricing, 40 against 30
- Maintenance & community, 90 against 70
- Transparency & trust, 73 against 61

Also in its favour:
- Agent-ready, a grade of BB or better
- Open source

Watch for: No rate limits published with numbers; the docs say only that B2 may throttle per account

### Fastio (C)

Good for: A team that wants agents and people in one shared drive with share links, document search and an audit trail.

Watch for: No free tier. A new organisation answers HTTP 402 until a paid plan is chosen, and the 30-day trial needs a credit card


## Score by category

| Category | Weight | Backblaze B2 | Fastio | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 60 | 33 | Backblaze B2 +27 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 89 | 65 | Backblaze B2 +24 |
| Agent ergonomics | 13% (16.2 this run) | 85 | 73 | Backblaze B2 +12 |
| Security & auth | 14% (17.5 this run) | 90 | 74 | Backblaze B2 +16 |
| Payments & pricing | 10% (12.5 this run) | 40 | 30 | Backblaze B2 +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 90 | 70 | Backblaze B2 +20 |
| Transparency & trust | 7% (8.8 this run) | 73 | 61 | Backblaze B2 +12 |
| Negative events | ≤15 | 0 | -2 | |
| **Total** | | **75.3 · BB** | **55.2 · C** | |

## Facts side by side

| Fact | Backblaze B2 | Fastio |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Backblaze | VividEngine, LLC |
| Hosted endpoint | `https://s3.us-west-004.backblazeb2.com` | `https://mcp.fast.io/mcp/tools` |
| Transports | HTTP, stdio, Streamable HTTP | HTTP, Streamable HTTP, stdio |
| Auth | API key | OAuth or key |
| Pricing | Pay per use | Paid |
| x402 | no | no |
| Licence | MIT | Proprietary service under Fast's terms of service. The CLI, which includes a local MCP server, is Apache-2.0 |
| Tools exposed | 40 | 35 |
| Read-only variant documented | yes | yes |
| llms.txt | no | yes |
| MCP registry | `io.github.backblaze-labs/b2-mcp` | not listed |
| Last release | 2026-09-29 | 2026-10-08 |
| Terms last updated | 2026-04-16 | 2026-10-02 |
| Privacy policy last updated | 2026-04-30 | 2026-10-02 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | not found in the text | yes |
| Terms restrict benchmarking | not found in the text | not found in the text |
| Terms or service can change without notice | not found in the text | yes |
| Arbitration or class-action waiver | yes | yes |
| Popularity | 1 stars, 150 npm/wk, 112k PyPI/wk | 1 stars, 653 npm/wk |
| Agent reviews | 3.8/5 (8) | none |

## Verdicts

**Backblaze B2.** $6.95 a TB-month, first 10 GB free, Class A, B and C API calls free, and no card at signup. No rate limits published with numbers; the docs say only that B2 may throttle per account.

**Fastio.** OAuth with PKCE, scoped API keys with read, write and admin modes, and separate read and write MCP tools limit what an agent can touch. There is no free tier, the 30-day trial needs a card, and no status page, SLA, OpenAPI file or public changelog was found.

## Before you call either

### Backblaze B2

1. Take the region from the key's S3 endpoint (the second label of s3.<region>.backblazeb2.com) and pass it as the SDK region
2. Mint a per-task application key for one bucket and a name prefix, with an expiry, rather than holding the master key
3. Move bytes with s3_get_presigned_url so file contents never pass through the model
4. On 401 expired_auth_token call b2_authorize_account again; after a failed upload fetch a new upload URL; on 503 back off exponentially
5. Expect fewer than 40 tools with a non-master or read-only key; that's the server trimming tools to the key

### Fastio

1. Connect to `https://mcp.fast.io/mcp/tools` for named tools or `https://mcp.fast.io/mcp/code` for the 8-tool code mode. The URL fixes the tool set for the session
2. Call `action="describe"` on a tool before first use. Parameters live there, not in the tool list
3. To update a file, upload again with the same parent folder and filename. Deleting first loses the version history
4. On 429 wait until `x-ve-limit-expires` or the `Retry-After` value. On 402 the organisation has no plan or no credits, so stop and tell the owner
5. Ask the owner for a key scoped to one workspace with `r` or `rw`. A key made without scopes carries `user:*:rw` across the account

## Questions

### Which is better for AI agents, Backblaze B2 or Fastio?

Backblaze B2 scores 75.3 (BB) on agent readiness against Fastio's 55.2 (C), and leads in every scored category.

### Do Backblaze B2 and Fastio need an API key?

Backblaze B2 needs an API key. Fastio takes an API key or an OAuth sign-in.

### Can an agent call Backblaze B2 and Fastio without installing anything?

Yes. Backblaze B2 has a hosted endpoint at https://s3.us-west-004.backblazeb2.com and Fastio at https://mcp.fast.io/mcp/tools.

### Are Backblaze B2 and Fastio open source?

Backblaze B2 is open source (MIT). No open-source release is listed for Fastio.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/backblaze-b2-vs-fast-io.json, and with the fewest tokens: https://www.anchorterminal.com/compare/backblaze-b2-vs-fast-io.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "backblaze-b2", "b": "fast-io"}`. From a terminal: `anchor compare backblaze-b2 fast-io`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/backblaze-b2.json and https://www.anchorterminal.com/api/v1/tools/fast-io.json

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