ibanchecker-mcp

MCP (Model Context Protocol) server for ibanchecker.cash. Gives AI assistants like Claude five finance tools backed by the ibanchecker.cash validation engine:

No IBAN data is logged or stored; validation runs in memory on Cloudflare's edge. See the security page for details.

Quick start: hosted remote server

The easiest path is the hosted endpoint. Nothing to install or deploy. Every tool except get_iban_format needs an API key (see API key).

https://mcp.ibanchecker.cash/mcp

Claude Code

claude mcp add --transport http ibanchecker https://mcp.ibanchecker.cash/mcp --header "Authorization: Bearer YOUR_API_KEY"

Claude Desktop (claude_desktop_config.json), via the mcp-remote bridge:

{
  "mcpServers": {
    "ibanchecker": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://mcp.ibanchecker.cash/mcp", "--header", "Authorization:${AUTH_HEADER}"],
      "env": {
        "AUTH_HEADER": "Bearer your-api-key-here"
      }
    }
  }
}

Local stdio server

Run the server locally over stdio (requires Node 18+):

{
  "mcpServers": {
    "ibanchecker": {
      "command": "npx",
      "args": ["-y", "@ibanchecker/mcp"],
      "env": {
        "IBANCHECKER_API_KEY": "your-api-key-here"
      }
    }
  }
}

Example

Calling validate_iban with DE89370400440532013000 returns:

{
  "valid": true,
  "iban": "DE89370400440532013000",
  "formatted": "DE89 3704 0044 0532 0130 00",
  "country_name": "Germany",
  "bank_name": "Commerzbank AG Cologne",
  "bic": "COBADEFFXXX",
  "bank_code": "37040044",
  "account_number": "0532013000",
  "sepa": true
}

When the API returns an error (for example a 429 rate limit, a 401 missing or bad key, or a 403 tool outside the key's plan), the tool result is flagged with isError: true and a human-readable message, so the assistant can react rather than crash.

API key

Every tool except get_iban_format needs an API key, and what a key can call follows its plan:

get_iban_format also works without a key, up to 100 requests an hour per IP. A free key covers 100 requests a month and arrives by email in seconds: get one at ibanchecker.cash/api-docs. A free account on the same address, at ibanchecker.cash/dashboard, opens the trials. Bulk validation and extraction count one request per IBAN. See ibanchecker.cash/pricing for higher volumes. Pass the key as:

• IBANCHECKER_API_KEY env var (stdio mode), or
• Authorization: Bearer <key> / x-api-key header (remote mode).

Project layout

.
├── bin/stdio.mjs      # npm CLI entry (published as `ibanchecker-mcp`)
├── shared/tools.mjs   # the 5 tool definitions, shared by both transports
└── worker/            # Cloudflare Worker (the hosted remote server)
    ├── src/index.ts
    └── wrangler.toml

Both the stdio CLI and the Worker register the exact same tools from shared/tools.mjs, so there is a single source of truth.

Self-hosting the Worker

The remote server is a Cloudflare Worker built on the Agents SDK. Deploy your own:

cd worker
npm install
npx wrangler deploy

Remove the routes block in worker/wrangler.toml (or point it at your own domain) and optionally set a server-wide key with npx wrangler secret put IBANCHECKER_API_KEY.

License

MIT. See LICENSE.