# `PaperTiger.WebhookDelivery.Adapter`
[🔗](https://github.com/EnaiaInc/paper_tiger/blob/v1.2.1/lib/paper_tiger/webhook_delivery/adapter.ex#L1)

Behaviour for delivering a signed webhook request.

PaperTiger signs the payload, builds the `Stripe-Signature` header, emits
the `[:paper_tiger, :webhook, :delivering]` telemetry event (observability
only), then calls the configured adapter's `deliver/1` with a
`PaperTiger.WebhookDelivery.Request`. The request includes the sandbox or
tenant namespace captured when the delivery was queued, so durable adapters
can persist work with the same context even though delivery runs in a
detached task.

Configure with:

    config :paper_tiger,
      webhook_delivery_adapter: MyApp.WebhookSink

The default is `PaperTiger.WebhookDelivery.HTTPAdapter`, which performs the
HTTP POST itself (the historical behavior). Override it when embedding
PaperTiger inside a system that must own webhook delivery durably (e.g. a
hosting layer that persists webhooks so they survive node restarts).

## Return contract

- `{:ok, %PaperTiger.WebhookDelivery.Response{}}` — the adapter has taken
  terminal ownership of this webhook. Either it delivered successfully, or
  it durably enqueued it and will deliver/retry itself. PaperTiger records a
  successful delivery attempt on the event and does **not** apply its own
  retry. A durable-enqueue adapter should return `%Response{status: 202}`.

- `{:error, reason}` — the adapter could not take ownership (HTTP non-2xx,
  transport error, failed to enqueue, ...). PaperTiger applies its own
  exponential-backoff retry exactly as it does for a failed built-in POST,
  and records `:failed` after the retry budget is exhausted.

An adapter must never return `{:ok, ...}` unless it has genuinely accepted
responsibility for the webhook. Returning `{:ok, ...}` after a best-effort
non-durable attempt is the one way to cause silent webhook loss; that is the
adapter's contract to uphold, and the reason delivery is an explicit
behaviour rather than a telemetry side effect.

# `deliver`

```elixir
@callback deliver(PaperTiger.WebhookDelivery.Request.t()) ::
  {:ok, PaperTiger.WebhookDelivery.Response.t()} | {:error, term()}
```

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