diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..25200c9
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,15 @@
+.PHONY: demo down
+
+# Spin up Postgres + the API in Docker, apply migrations, seed sample
+# subscriptions, and print the spending summary. Safe to re-run.
+demo:
+	cd api && docker compose up -d --wait
+	cd api && \
+	  DATABASE_URL="postgres://subtrack:devpassword@localhost:5432/subtrack?sslmode=disable" \
+	  API_KEY=dev-local-key \
+	  go run ./cmd/migrate up
+	cd api && BASE_URL=http://localhost:8080 API_KEY=dev-local-key ./scripts/demo.sh
+
+# Stop the stack and remove its data volume.
+down:
+	cd api && docker compose down -v
diff --git a/README.md b/README.md
index 8f1bc5e..fc1a88b 100644
--- a/README.md
+++ b/README.md
@@ -40,12 +40,25 @@ agent's choices small and unambiguous.
 Requires [Docker](https://docs.docker.com/), Go (see `api/go.mod`), and
 [uv](https://docs.astral.sh/uv/).
 
+### One command demo
+
+```sh
+make demo
+```
+
+This starts Postgres 16 (5432) and the API (8080) in Docker, applies migrations, seeds 3 sample
+subscriptions, and prints the spending summary. Run `make down` afterwards to stop the stack and
+remove its data volume.
+
+### Manual setup
+
 ```sh
 # 1. Start the backend: Postgres 16 (5432) and the API (8080).
 cd api
 cp .env.example .env   # optional — compose ships working dev defaults
 docker compose up -d
-make migrate-up
+DATABASE_URL="postgres://subtrack:devpassword@localhost:5432/subtrack?sslmode=disable" \
+  API_KEY=dev-local-key make migrate-up
 
 # 2. Sanity check.
 curl http://localhost:8080/healthz
@@ -59,6 +72,10 @@ export SUBTRACK_API_KEY=dev-local-key   # matches api/.env.example
 uv run subtrack-mcp
 ```
 
+> Note: `make migrate-up` runs on the host via `go run`, so it needs `DATABASE_URL` (or
+> `POSTGRES_*`) and `API_KEY` set in your shell — `.env` is only read by `docker compose`, not by
+> the Go binaries.
+
 `SUBTRACK_API_URL` and `SUBTRACK_API_KEY` are mandatory — the MCP server fails fast at startup if
 either is missing. Point your MCP client at `uv run subtrack-mcp` with the same two variables set,
 and it connects over stdio.