Ordering

By default Ensue delivers events as fast as your destination allows, with retries interleaving. That is right for most webhooks. Some are not: an order.updated that arrives before the order.created before it, or two updates to one record processed at once.

Ordering gives you a line per key. Events that share a key value are handed out in the order they arrived; events with different values do not wait for each other.

Configure it

Set ordering on a flow:

{
  "ordering": { "key": ["data.object.id"], "max": 1, "name": "order" }
}

Field	Meaning
key	One to four paths in the request. Events agree on every value to share a line.
max	How many events of one key may be out at once. 1 (default) is strict order; up to 20 allows concurrency within a key.
name	Optional. Two flows that use the same name share lines, so a Stripe event and a Shopify event for the same order wait for each other. Without a name, a key belongs to its flow.

What this means in practice

• A failing event holds its line. While event A is retrying, later events with the same key wait behind it. Other keys keep flowing.
• A dead letter releases the line. When an event gives up (it becomes a dead letter), the next event moves on, and the timeline records why.
• A missing key value is delivered unordered, and the timeline says so. Putting all of them in one shared line would make unrelated events wait on each other.
• Unrelated things that happen to share a key value only wait for each other, so choose a key that identifies one thing.

Guarantees

Ensue guarantees order per key, for one flow. It does not offer global ordering across a source, or across different keys, and delivery stays at least once. A redelivered event may be seen again, in its place in line.