# `Outboxer.Storage.SQLite`
[🔗](https://github.com/epinault/outboxer/blob/v0.1.0/lib/outboxer/storage/sqlite.ex#L2)

SQLite storage, for single-node applications.

SQLite allows one writer at a time, which shapes two decisions:

  * **Delivery happens outside any transaction.** Holding the write lock
    while a relay talks to a broker would stall every other write in your
    application. A batch is read, delivered, and then removed with a single
    short statement.
  * **Exclusivity comes from the supervision tree.** There is exactly one
    worker process per partition on the node, and a SQLite database belongs
    to one node, so no database lock is needed.

The consequence: do not point two running nodes (or two Outboxer instances
with the same outboxes) at the same SQLite file. They would deliver the
same messages twice and out of order. For a replicated setup such as
LiteFS, run the relay on the primary only and start the other nodes with
`relay: false` so they can still publish.

`serialize_writes` and `notify` have no effect here: writers are already
serialised by SQLite, and there are no other nodes to notify.

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*Consult [api-reference.md](api-reference.md) for complete listing*