splitwise-mcp

MCP server for Splitwise — natural-language expense and group management via the Splitwise API.

• npm: npmjs.com/package/splitwise-mcp
• Source: github.com/chrischall/splitwise-mcp

Setup

Option A — npx (recommended)

Add to .mcp.json in your project or ~/.claude/mcp.json:

{
  "mcpServers": {
    "splitwise": {
      "command": "npx",
      "args": ["-y", "splitwise-mcp"],
      "env": {
        "SPLITWISE_API_KEY": "your-api-key-here"
      }
    }
  }
}

Option B — from source

git clone https://github.com/chrischall/splitwise-mcp
cd splitwise-mcp
npm install && npm run build

Then add to .mcp.json:

{
  "mcpServers": {
    "splitwise": {
      "command": "node",
      "args": ["/path/to/splitwise-mcp/dist/index.js"],
      "env": {
        "SPLITWISE_API_KEY": "your-api-key-here"
      }
    }
  }
}

Or use a .env file in the project directory with SPLITWISE_API_KEY=\x3Cvalue>.

Getting your API key

1. Go to splitwise.com/apps/register
2. Register an app (name and description can be anything)
3. Copy the API key from the app detail page

Authentication

API key auth — no login flow or token rotation. The key is attached to every request as Authorization: Bearer \x3Ckey>.

Tools

User

Groups

Friends

Expenses

Utilities

Workflows

Add an expense to a group:

sw_list_groups → find group ID for "vacation"
sw_create_expense(group_id, "Dinner", "80.00", split_equally: true)

Add someone to a group:

sw_list_friends → find Meredith's user_id
sw_get_group(id) → check if Meredith is already in members[]
sw_add_user_to_group(group_id, user_id) → if not

Custom split (you paid, split 60/40):

sw_get_current_user → your user_id
sw_list_friends → other person's user_id
sw_create_expense(group_id, "Hotel", "200.00", users: [
  { user_id: yours, paid_share: "200.00", owed_share: "120.00" },
  { user_id: theirs, paid_share: "0.00", owed_share: "80.00" }
])

Search and edit an expense:

sw_list_expenses(group_id, dated_after: "2026-01-01") → find expense ID
sw_update_expense(expense_id, description: "Corrected description", cost: "95.00")

Notes

• cost is always a decimal string (e.g. "25.00")
• split_equally: true and users array are mutually exclusive
• For custom split updates, the full users array is required — the API replaces the entire split
• sw_delete_expense is a soft delete; restoration requires the Splitwise web app
• API default for sw_list_expenses is 20 results when limit is omitted