| local-first | app design where local user data remains useful without network |
| offline-first | UX/network strategy that assumes offline can happen anytime |
| source of truth | data the app must not lose or treat as disposable |
| cache | data that can be refetched or regenerated |
| derived index | search/vector/summary data rebuilt from source data |
| migration | versioned data/schema transition |
| WAL | SQLite write-ahead log, stored beside the main DB as -wal |
| checkpoint | process that moves WAL frames into the main SQLite DB file |
| backup | complete recovery artifact |
| export | user-facing artifact for inspection or portability |
| restore | process that applies a backup to a clean or existing app state |
| OPFS | Origin Private File System, browser-private file storage |
| mutation | durable record of a local action to sync later |
| idempotency key | stable key that makes retrying the same action safe |
| conflict | two changes cannot be applied automatically without product semantics |
| CRDT | conflict-free replicated data type for automatic multi-writer merges |
| tombstone | retained delete marker used for sync and conflict handling |
| secure store | platform key/secret storage such as Keystore, Keychain, or Stronghold |