Tmp.DH2HBD8750

Access Splitwise expense and group data via MCP. Use when the user asks about Splitwise expenses, groups, friends, or balances, or wants to add, edit, or delete expenses. Triggers on phrases like "add that expense to Splitwise", "split this with the vacation group", "make sure Meredith is in that group", "what do I owe", or any request involving shared expenses or group management in Splitwise. Requires splitwise-mcp installed and the splitwise server registered (see Setup below).

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:

json

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

Option B — from source

bash

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

Then add to .mcp.json:

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=<value>.

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 <key>.

Tools

User

Tool	Description
sw_get_current_user	Get the authenticated user's profile (id, first_name, last_name, email)

Groups

Tool	Description
sw_list_groups	List all groups with id, name, and members[]
sw_get_group(id)	Get a single group's details including members and balances
sw_create_group(name, group_type?, simplify_by_default?)	Create a new group (group_type: apartment, house, trip, other)
sw_add_user_to_group(group_id, user_id?)	Add a user by user_id (preferred) or first_name + last_name + email
sw_remove_user_from_group(group_id, user_id)	Remove a user from a group

Friends

Tool	Description
sw_list_friends	List all friends with id, first_name, last_name, email

Expenses

Tool	Description
sw_list_expenses(group_id?, friend_id?, dated_after?, dated_before?, limit?, offset?)	List or search expenses
sw_get_expense(id)	Get full details of a single expense
sw_create_expense(group_id, description, cost, split_equally? | users?)	Create an expense — equal split or custom per-person split
sw_update_expense(expense_id, ...)	Edit an existing expense (custom split requires full users array)
sw_delete_expense(id)	Soft-delete an expense

Utilities

Tool	Description
sw_get_notifications	Recent activity feed for the current user
sw_get_categories	Hierarchical list of expense categories (use id as category_id)
sw_get_currencies	List of supported currency codes

Workflows

Add an expense to a group:

text

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

Add someone to a group:

text

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):

text

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:

text

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