Expense MCP Server

Expense

Expense is a seamless receipt tracking solution: receipts are automatically sent via email, mileage uses the tax rate provided by the IRS, and a smart AI assistant does your data entry so that you can forget about the process altogether.

PRODUCT.md is the map: what the product is, how it works, the pages a person uses, the architecture and data model, and the vocabulary. This file is the front door; that one is the orientation.

Screenshots

What it does

Receipts come in from a photo, a screenshot, a PDF, the clipboard, a connected Fastmail or Gmail mailbox, or an MCP assistant; each one is read for merchant, amount and category, filed under an IRS Schedule C line, and kept with its image. Drives are mapped and priced at the IRS rate for the trip date and type. The year leaves as a PDF per report, with the receipts attached, or as one ZIP of everything. A warranty document dropped on the warranties page becomes a record you can find by how soon coverage ends.

Free, no card, no ads, no paid tier. Not built for corporate expense policy, approvals, or double-entry bookkeeping. The full tour, with the pages and the rules behind each one, is in PRODUCT.md.

AI assistants (MCP)

The app speaks the Model Context Protocol at https://expense.labnotes.org/mcp. An assistant connects with OAuth — you sign in and click Allow — so there are no API keys. A connected assistant can capture a receipt, log a drive, answer questions about your spending, manage reports, and match a bank statement.

// Claude — .mcp.json (no headers needed: the client discovers OAuth)
{
  "mcpServers": {
    "expense": {
      "type": "http",
      "url": "https://expense.labnotes.org/mcp"
    }
  }
}

The reference is docs/mcp.md; the tools are listed in PRODUCT.md.

Accounts

Email is the login name, hashed with scrypt, with a signed-cookie session. Everything belongs to an account; an account has several users; accounts are fully isolated from each other. Sign up for a new one, or join an existing one with the 8-character invite code in Settings. Image keys are namespaced per account, so two accounts can never collide. More detail in PRODUCT.md and docs/accounts.md.

How it is built

One app, one Postgres database, no monorepo. React Router v8 in framework mode (SSR), where the URL tree is the filesystem; Prisma 8 contract-first, so prisma/contract.prisma is the schema and there are no migration files; images stored as bytes in Postgres rather than in object storage. Deployed on Vercel plus Supabase Postgres, where a push to main deploys. The diagrams are in PRODUCT.md.

Run it locally with pnpm dev; the environment variables, the connection poolers and the deploy path are in docs/operations.md and docs/deploy.md.

Documentation