Files
tegwick e00c160a43 research: Joplin deep dive (SQLite-local/Markdown-on-sync, interchange-format attach, E2EE content opacity); UC-60/61
Architecturally distinct from the Obsidian/Roam/Notion trio: content is
Markdown, the local store is SQLite, and the sync representation is a
folder of per-item Markdown+metadata files on a backend of choice
(filesystem, WebDAV, Nextcloud, Dropbox, OneDrive, S3, Joplin
Server/Cloud). Two new findings: (1) attach the sync/interchange mirror,
not the app or the SQLite store, offline and app-independent, landing on
INTENT's WebDAV/Nextcloud/S3 backends (UC-60, distinct from native
on-disk store UC-40 and app-files UC-53); (2) E2EE => content opacity, a
proposed twelfth capability spectrum for encrypted-at-rest shards (UC-61).
Also: Joplin is the file-sync-daemon boundary case (attach the mirror as
pages, never re-sync); store-minted page-level :/id links (addressing
spectrum middle); dual surface (plugin host + local Data API on
localhost:41184). Enriched UC-31/36/38/40/51/55. Catalog now 61 UCs.
Architecture for SHARD-WP-0002 T11/T14: interchange-format attach,
content-opacity field, local-REST sub-mode, format-aware file-store
profiles.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-06-14 14:21:31 +02:00
..

260614 — Joplin deep dive (SQLite-local, Markdown-on-sync, interchange-format attach)

Date: 2026-06-14

What this is

A focused study of Joplin — the open-source Markdown note app — read through shard-wiki's lens. Joplin looks like "open-source Obsidian" but is a genuinely different point in the space: content is Markdown, the local store is SQLite, and the sync representation is a folder of per-item Markdown+metadata files on a backend you choose (filesystem, WebDAV, Nextcloud, Dropbox, OneDrive, S3, Joplin Server/Cloud). It also ships end-to-end encryption and is itself a sync layer over heterogeneous storage.

Distinctive material:

  • Architecture — SQLite local store (documented schema); Markdown content; notebooks → notes → resources + tags + to-dos; 32-char item IDs; :/<id> note links (rename-stable, page-level)
  • Sync — serialized to plain-text items on a chosen target; tombstones; conflict notes (keep-both) → enables the "attach the sync mirror, not the app" pattern on WebDAV/Nextcloud/S3
  • E2EE — items encrypted before leaving the device → content opacity (ciphertext at rest)
  • Extension surfaces — a plugin API (joplin.data/workspace/contentScripts/ views) and a local Data API (REST on localhost:41184, token) used by the Web Clipper; plus JEX/Markdown/RAW export

Contents

Path Role
findings.md Architecture, sync/interchange attach, E2EE/content-opacity, plugin + Data API surfaces, capability profile, INTENT mapping, UC seeds, architecture notes, sources

Status

Initial deep dive complete. Two new use cases promoted to spec/UseCaseCatalog.md (UC-60 attach a tool's documented sync/interchange representation on third-party storage without the app; UC-61 attach an encrypted-at-rest shard with content opacity); UC-31/36/38/40/51/55 enriched. Logged for SHARD-WP-0002 (T11, T14): the interchange/sync-representation attach surface, content opacity as a proposed twelfth capability spectrum, a local-REST attach sub-mode, and format-aware file-store profiles.

Key takeaways recorded: the best attach surface is often a tool's interchange/sync representation (offline, app-independent — Joplin items on Nextcloud/WebDAV/S3, the INTENT-named backends), not its live store or API; encryption-at-rest demands a content-opacity capability so encrypted shards degrade to backup/structure-shell; and Joplin is the file-sync-daemon boundary case — shard-wiki attaches its mirror as pages and never re-syncs (not-a-sync-daemon).