---
title: "Concepts"
description: "How Logbun is split between a runtime-neutral core, destination adapters, and reliability backends."
---

> Documentation Index
> Fetch the complete documentation index at: https://logbun-docs.abshahin.workers.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Concepts

Logbun is an audit-event pipeline. Callers emit typed actions; the library redacts, caps, assigns a UUIDv7 `id`, optionally seals a hash chain, admits the event through a reliability journal, batches it in RAM, and inserts it into a destination adapter.

The package root is ES2022 / Web APIs only. Runtime-specific storage is reached through explicit exports:

```text
logbun (root) ── MemoryReliabilityAdapter (volatile)
          ├─ logbun/durability/filesystem ── Node/Bun/Deno WAL + files
          └─ logbun/durability/cloudflare ── Workers DO SQLite
```

Destination adapters (`IAdapter`) store queryable records. Reliability adapters own the journal and DLQ. Durable mode requires a **persistent** reliability adapter; missing or `persistent: false` throws in the constructor.

- **Pipeline** — [fire / fireAsync → journal → RAM queue → destination](/concepts/pipeline)
- **Durability** — [volatile vs durable, pre-ready buffer, fire vs fireAsync](/concepts/durability)
- **Reliability** — [Journal, DLQ states, invariants, host maintenance](/concepts/reliability)
- **Tenancy** — [single_database vs database_per_tenant, requireTenantId](/concepts/tenancy)
- **Integrity** — [Optional prevHash / contentHash chain, restore, verify](/concepts/integrity)

Source: https://logbun-docs.abshahin.workers.dev/concepts/index.mdx