Todo API

A learning project for Elixir, Phoenix, Ecto, and CockroachDB. Pure REST JSON API — no HTML, no frontend.

Stack

• Elixir / Phoenix (API mode)
• Ecto (database layer)
• CockroachDB (via Docker)

Running locally

1. Start the database: docker-compose up -d
2. Create and migrate: mix ecto.setup
3. Start the server: mix phx.server

Endpoints

Method	Path	Description
GET	/api/todo	List all todos
GET	/api/todo/:id	Get one todo
POST	/api/todo	Create a todo
PUT	/api/todo/:id	Update a todo
DELETE	/api/todo/:id	Delete a todo

Todo shape

{
  "id": "UUID", //this is automatically generated
  "customer": "string",
  "type": "string",
  "status": "string",
  "notes": "string", // can't do text as it's isn't usuable by roach
  "deadline": "datetime",
  "inserted_at": "auto",
  "updated_at": "auto"
}

---

Roadmap

Phase 1 — Project setup

• Scaffold the Phoenix API project
• Write a docker-compose.yml for CockroachDB
• Configure Ecto to connect to CockroachDB
• Verify the connection with mix ecto.create

Concepts: Phoenix project structure, Mix, config layers, Ecto Repo

Phase 2 — Data layer

• Write a migration (defines the todos table in the DB)
• Write the Todo Ecto schema (Elixir struct that maps to the table)
• Write the Todos context (module that owns all DB queries)

Concepts: Ecto migrations, schemas, changesets, contexts

Phase 3 — API layer

• Add routes to router.ex
• Write a TodoController with all 5 actions
• Wire each action to a context function
• Return proper JSON responses

Concepts: Phoenix router, controllers, JSON responses, HTTP status codes

Phase 4 — Smoke test

• Test all endpoints with curl or a REST client
• Handle the unhappy paths (missing record, bad input)