Backblaze B2 MCP Server

A local MCP server that exposes Backblaze B2 Cloud Storage to MCP clients (Claude Desktop, Claude Code, etc.) — via the native B2 API (b2_* tools, the full feature set) and a B2 S3-compatible tool set (s3_* tools, for interoperability).

This is an unofficial, community project. It is not affiliated with or endorsed by Backblaze.

Developed by Muhammed Ehab, for the dev community. 🤝

Requirements

• Node.js ≥ 20

• A Backblaze B2 account (a free tier is available) and an application key (see below)

Related MCP server: S3 MCP Server

Installation

git clone https://github.com/<your-username>/backblaze-b2-mcp.git
cd backblaze-b2-mcp
npm install
npm run build

Getting a Backblaze B2 application key

Each user of this server needs their own B2 application key — never share a key or commit one to source control.

1. Sign in to the Backblaze B2 dashboard.

2. Go to Account → App Keys.

3. Click Add a New Application Key.

   • Give it a name.

   • For safety, restrict it to a single bucket if you can (rather than granting account-wide access), and only grant the capabilities you actually need (e.g. listBuckets, readFiles, writeFiles, deleteFiles for typical use).

4. Backblaze shows the keyID and applicationKey once, at creation time. Copy both immediately — the applicationKey cannot be retrieved again later.

Configuration

Copy .env.example to .env and fill in your own credentials:

cp .env.example .env

Configure in Claude Desktop / Claude Code

Add to your MCP client config (e.g. claude_desktop_config.json):

{
  "mcpServers": {
    "backblaze-b2": {
      "command": "node",
      "args": ["/absolute/path/to/backblaze-b2-mcp/dist/server.js"],
      "env": {
        "B2_APPLICATION_KEY_ID": "your_key_id",
        "B2_APPLICATION_KEY": "your_application_key"
      }
    }
  }
}

Use an absolute path to dist/server.js. Restart your MCP client after editing its config.

Available tools

Native B2 (b2_*)

S3-compatible (s3_*) — a smaller interoperability subset:

Notes & caveats

• Backblaze does not expose a billing/invoices API, so b2_get_account_info's usage figures are an estimate (capped at the first 1000 files per bucket) — check the B2 web dashboard for exact costs.

• On a bucket with the default "keep all versions" lifecycle, s3_delete_object (like a real S3 client's DeleteObject) only hides the object — it does not free the underlying storage or let you delete the bucket. Use b2_delete_file_version for a true, permanent delete, or configure bucket lifecycle rules to expire hidden versions automatically.

• b2_delete_bucket, b2_delete_file_version, b2_delete_key, and s3_delete_object are irreversible.

Development

• npm run dev — run the server directly with tsx

• npm test — run the unit test suite (mocked network, no live B2 account required)

• npm run build — compile to dist/