---
title: "OpenAI Responses API: Bank Data via MCP | BankBridge"
description: "Give your OpenAI Responses API app live bank data with one remote MCP tool block. About 6 lines of code, then ask it to total last month's spending."
url: "https://bankbridge.money/docs/responses-api"
---
[← All integrations](https://bankbridge.money/docs)

OpenAI Responses API

# First-class MCP tool type.

Building your own GPT-powered app with the OpenAI API? Register BankBridge as an MCP tool. OpenAI proxies the tool calls server-side. No client-side MCP runtime needed.

Step 01

## Add the tool to your request.

POST /v1/responses

```
{
  "model": "gpt-4.1",
  "input": "How much did I spend on restaurants last month?",
  "tools": [
    {
      "type": "mcp",
      "server_label": "bankbridge",
      "server_url": "https://bankbridge.money/api/mcp",
      "headers": {
        "Authorization": "Bearer bbk_your_api_key_here"
      },
      "require_approval": "never"
    }
  ]
}
```

Grab a key from [your dashboard](https://bankbridge.money/dashboard).

Step 02

## Verify it works.

Send the request. OpenAI fetches the tool list from BankBridge, lets the model call tools as needed, and streams results back. Expected first tool call:

expected

```
list_transactions({ category: "FOOD_AND_DRINK", start_date: "2026-03-01", end_date: "2026-03-31" })
```

What about per-user keys?

If you’re shipping a consumer app where each user should link their own bank, pass their BankBridge API key in the `Authorization`header per-request. Your app holds one key per user (collect at signup or via an “Connect BankBridge” button that deep-links to our dashboard).

Troubleshooting

401 Unauthorized on every call.

The API key is missing, typo'd, or got revoked. Check the Authorization header starts with \`Bearer \` (note the space) and ends in a key you still own.

**Fix:** Paste a fresh key from [Settings](https://bankbridge.money/dashboard/settings).

Tools return setup\_required.

Your BankBridge account has no active subscription yet, or it was canceled or is past due. The connection itself works; each tool answers with the link that finishes setup.

**Fix:** Visit [Settings](https://bankbridge.money/dashboard/settings) to start or restore your subscription, then connect a bank.

Tools return a NO\_CONNECTIONS warning.

You haven't linked a bank yet.

**Fix:** Visit [Connect a bank](https://bankbridge.money/dashboard/connect) . The bank-connect flow opens automatically, ~30 seconds.

Problems? Email [hello@bankbridge.money](mailto:hello@bankbridge.money).