Sovereign Operator-Owned Subscriber-List Durability under Ephemeral Serverless Runtime.

Newsletter subscriber list lives on operator hardware, baked into the deployment artefact. 20 claims.

A method by which an operator-controlled JSONL canonical subscriber-event store at an operator-controlled filesystem location is mirrored at build time into a programming-language seed module baked into the deployment artefact of an ephemeral serverless runtime. At runtime the function imports the seed as baseline state, maintains a runtime-ephemeral overlay store, and computes the working subscriber list by latest-action-wins reconciliation. New signups are dispatched to an operator-notification channel so the operator may, on operator cadence, append to the canonical store and rebake. Permits sovereign operators to retain canonical custody of subscriber state on operator-controlled hardware while running the subscribe endpoint on an ephemeral serverless platform, without depending on any external durable-storage service. Filed 19 May 2026 as GB2611684.8.