Scale & volume ops
Throughput, rate limits, and operating habits when volume leaves the pilot stage.
Throughput vs wallet burn correlation
Join QPS and accepted-throughput charts to prepaid debit burn on the same UTC window so finance sees scale cost — not a vanity send graph.
Volume ops: queues and named owners
Runbooks for throughput at scale — named queues, shard owners, and burn watch so product and finance open one board without hero threads.
Queue overflow: stop, do not silent-drop
When a send queue overflows, fail closed with countable status and protect prepaid — never silent-drop intents that finance cannot reconcile.
Rate-limit gate before you allow bursts
Prod gate: document limits and backoff before marketing “unlimited” bursts — reject and Retry-After must protect prepaid before campaigns open the tap.
Pilot throughput: honest ceiling
Set a real pilot throughput ceiling so first volume does not surprise the prepaid wallet — named QPS and daily caps before marketing “ready for scale.”