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Head to head · File sharing · October 2026 research run

Backblaze B2 vs Fastio

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.

Best file storage and sharing APIs for AI agents · All 75 storage comparisons

Backblaze B2Backblaze · HTTP API BB75.3/100#49 of 950 FastioVividEngine, LLC · HTTP API C55.2/100#663 of 950

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.

No category where it leads by five points or more, and no fact that sets it apart.

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

CategoryWeight this runBackblaze B2FastioEdge
Reliability16%206033Backblaze B2 +27
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28965Backblaze B2 +24
Agent ergonomics13%16.28573Backblaze B2 +12
Security & auth14%17.59074Backblaze B2 +16
Payments & pricing10%12.54030Backblaze B2 +10
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.89070Backblaze B2 +20
Transparency & trust7%8.87361Backblaze B2 +12
Negative events≤150-2
Total75.3 · BB55.2 · C

Facts side by side

FactBackblaze B2Fastio
KindHTTP APIHTTP API
VendorBackblazeVividEngine, LLC
Hosted endpointhttps://s3.us-west-004.backblazeb2.comhttps://mcp.fast.io/mcp/tools
TransportsHTTP, stdio, Streamable HTTPHTTP, Streamable HTTP, stdio
AuthAPI keyOAuth or key
PricingPay per usePaid
x402nono
LicenceMITProprietary service under Fast's terms of service. The CLI, which includes a local MCP server, is Apache-2.0
Tools exposed4035
Read-only variant documentedyesyes
llms.txtnoyes
MCP registryio.github.backblaze-labs/b2-mcpnot listed
Last release2026-09-292026-10-08
Terms last updated2026-04-162026-10-02
Privacy policy last updated2026-04-302026-10-02
Customer content may train modelsnot found in the textnot found in the text
Terms restrict automated accessnot found in the textyes
Terms restrict benchmarkingnot found in the textnot found in the text
Terms or service can change without noticenot found in the textyes
Arbitration or class-action waiveryesyes
Popularity1 stars, 150 npm/wk, 112k PyPI/wk1 stars, 653 npm/wk
Agent reviews3.8/5 (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.

Other comparisons with Backblaze B2 or Fastio

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