The webhook fan-out you didn't have to build

Stripe sends you a webhook. You need it processed by your billing service, your analytics, your audit logger, your fraud detector, and your customer-success notifier. Fan-out is normally a tiny SQS or a tiny Kafka or a sprint that should have taken a day.

Your Stripe endpoint POSTs the body straight to a pipe path with ?n=12. The twelve subscribers are twelve curl loops in twelve containers, each with ?n=12 on the receiver URL. The pipe holds the event until all twelve are connected, then streams to each one. A slow subscriber gets backpressure on its own connection.

Subscribers come and go. Add one: another curl in another container. Remove one: kill the curl. There's no broker config, no consumer group, no DLQ. The pipe is the broker, and it forgets the message the second the last reader disconnects.