---
name: sumly
description: Read and update an indie founder's revenue and visitor numbers in Sumly (sumly.dev) through its MCP server or HTTP API. Use when asked about MRR, revenue, payments, customers, churn, costs, profit, visitors, traffic sources, which source brings paying customers, or Sumly setup.
---

# Sumly

Sumly puts a founder's money (from Stripe, Paddle, Lemon Squeezy, Polar, Creem, RevenueCat, the App Store, Google Play and others) beside the visitors of their sites, and traces each payment to the source of the buyer's first visit. A workspace has projects; each project is one site or app.

## Connect

Prefer MCP: `https://sumly.dev/mcp` (Streamable HTTP, OAuth sign-in). The person signs in once; no key is copied. Without MCP, use the HTTP API at `https://sumly.dev/api` (spec: https://sumly.dev/openapi.json) with a project key as `Authorization: Bearer <key>`:

- read key `rk_sumly_…`: reads only (made by the owner under Connect an assistant);
- secret key `sk_sumly_…`: sends events, costs and payments, and reads (server only);
- site key `sl_…`: public, sends events only.

## Which tool answers what

| Question | MCP tool | API |
|---|---|---|
| MRR, ARR, customers, trials, churn, last 30 days | `overview` | `GET /v1/stats/overview` |
| Money in a period (today, this month, a range), by project, country or provider | `revenue_breakdown` | |
| Recent payments, one customer's payments | `payments`, `customers` | |
| How a number moved over time | `metric_trend`, `months` | |
| Visitors, pages, places, devices | `traffic` | `GET /v1/stats/visitors` |
| Which source brings paying customers | `visitors`, `roi` | `GET /v1/stats/sources` |
| Who is on the site now | `live` | |
| Costs, burn, profit | `costs` | `POST /v1/costs` to add |
| Is everything set up | `check_setup`, `setup_guide` | `GET /v1/ping` |

Some tools (late payers, subscriptions, settings, goals) appear only once they are switched on for the account; `tools/list` shows what this account has.

## Rules

- Amounts are in euros unless the answer says otherwise. Say which project (`scope`) and period a number is for.
- When a tool returns `error`, tell the person what it says; do not guess numbers.
- Ask before a change that cannot be undone (tools marked destructive). Sumly never sells or upgrades a plan through a tool.
- The demo (https://sumly.dev/demo) has made-up numbers; its keys answer 401.