@spendcap/journal

An append-only, hash-chained, HLC-ordered event journal. Zero dependencies.

npm install @spendcap/journal

import { Journal, MemoryJournalStore } from "@spendcap/journal";

const journal = await Journal.open({
  store: new MemoryJournalStore(),
  device: "laptop",
  lane: "laptop",
});

await journal.appendOne({
  type: "note.written",
  schema: { id: "note", version: 1 },
  payload: { text: "hello" },
});
const events = await journal.readAll();

History is never mutated. Events are never edited, reordered or deleted. Everything else is a projection of this and may be discarded and rebuilt.

Tamper-evident. Each lane is hash-chained, so corruption or rewriting is detectable rather than silent.

No authoritative device. Each device writes only its own lane and replicates foreign ones; merge is a set union of immutable lanes and never rewrites history.

Global order is derived on read, never stored — computed from Hybrid Logical Clocks. Persisting an order would reintroduce an authority.

Stores are ports: MemoryJournalStore and FileJournalStore ship; bring your own for anything else.

Ships without a test suite. npm run check at the repository root exercises the claims above against the built output.

Apache-2.0.