Transactional enqueue: insert jobs inside your database transaction, so a job exists if and only if the business write committed.

Postgrex.transaction(MyApp.Pool, fn conn ->
  create_order!(conn, order)

  {:ok, _job} =
    Belay.Txn.insert(conn, MyApp.Belay, MyApp.FulfillOrder.new(%{"id" => order.id}))
end)

Works identically with an Ecto repo (anything exporting query!/2):

MyApp.Repo.transaction(fn ->
  order = MyApp.Repo.insert!(changeset)

  {:ok, _job} =
    Belay.Txn.insert(MyApp.Repo, MyApp.Belay, MyApp.FulfillOrder.new(%{"id" => order.id}))
end)

Belay itself takes no Ecto dependency — the bridge is duck-typed over query!, and the SQL is exactly what the Postgres storage adapter runs.

Wake-ups are transactional too. When the instance has the :postgres notifier configured, the poke is issued with pg_notify inside the same transaction — Postgres delivers notifications only on commit, so workers wake at the exact moment the job becomes real, and a rollback wakes nobody. Without that notifier, committed jobs are picked up by the adaptive polling floor (busy_poll..poll_interval).

Requires the named Belay instance to be running in this VM (it supplies worker defaults, the clock, and notifier configuration), and Postgres storage.