InMemory Backend

Intended use

in_memory backend is best for:

• local development,
• schema/validation testing,
• lightweight experimentation where persistence is not required.

Behavior

• Data is process-memory only and is lost on restart.
• Topic/message limits are enforced with eviction.
• No shared state across replicas or pods.
• Supports live watch subscriptions (live-only delivery).
• Supports replay batch retrieval for from_id and from_date.
• Uses in-process fanout only, so subscriptions/replay are node-local.

Configuration

notification_backend.kind: in_memory

Available knobs:

• max_history_per_topic (default 1)
• max_topics (default 10000)
• enable_metrics (default false)

Per-schema storage_policy fields are currently not supported on in_memory and are rejected at startup.

Production suitability

Not recommended for production because:

• no durability,
• no HA replication,
• no cross-instance consistency,
• replay/watch history is limited to local in-memory retention.