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Hjarni REST API

The REST API is for scripts, automations, and custom integrations. If you are connecting an AI assistant like ChatGPT or Claude, use the MCP server instead.

Overview

Base URL
https://hjarni.com/api/v1
Auth
Bearer token
Content type
application/json
Resources
Me, dashboard, search, notes (including file attachments), containers, and tags
Rate limit
100 requests per minute per token. Exceeding it returns 429 with a Retry-After header.

Authentication

  1. Go to Settings > Connections in Hjarni.
  2. Create a token for your integration.
  3. Send it in the Authorization header as a Bearer token.
curl https://hjarni.com/api/v1/notes \
  -H "Authorization: Bearer YOUR_API_TOKEN"

Pagination

List endpoints accept page (default 1) and per_page (default 25, max 100). Two exceptions return the full list without pagination: GET /containers/:id/children and GET /notes/:id/linked. Metadata is returned in response headers:

X-Total-Count
Total number of records matching the query
X-Page
Current page number
X-Per-Page
Items per page

Me

GET /api/v1/me

The account behind the token: user and plan, onboarding state, team memberships, and note limits, plus a token block describing the token itself. Folder-scoped tokens get only the user and token blocks.

Response example
{
  "user": {"id": 1, "first_name": "Evert", "email_address": "you@example.com", "plan": "pro"},
  "token": {"id": 7, "name": "smoke-test", "scope_container": null},
  "onboarding": {"completed": true, "missing_steps": [], "signals": {...}},
  "teams": [{"id": 3, "name": "Acme", "role": "owner", "notes_used": 12, "notes_limit": 25}],
  "limits": {"notes_used": 42, "notes_limit": null},
  "suggestions": {"create_team": false}
}

Dashboard

GET /api/v1/dashboard

Overview of your personal knowledge base with counts and recent notes.

Response example
{
  "inbox_count": 3,
  "notes_count": 42,
  "archived_count": 7,
  "containers_count": 8,
  "tags_count": 12,
  "recent_notes": [
    {
      "id": 1,
      "title": "Weekly review",
      "body": "# Decisions\n\n...",
      "summary": "Review of the week",
      "summary_stale": false,
      "source_url": null,
      "archived": false,
      "favorited": false,
      "position": 1,
      "lock_version": 2,
      "created_at": "2026-03-15T10:00:00Z",
      "updated_at": "2026-03-15T10:00:00Z",
      "tag_list": "review,planning",
      "tags": [{"id": 1, "name": "review"}, {"id": 2, "name": "planning"}],
      "container": {"id": 5, "name": "Work"},
      "files": []
    }
  ]
}

Notes

GET /api/v1/notes

List personal notes. Paginated.

scope
"archived", "inbox", "favorited", or omit for active notes. Trashed notes have their own endpoint: GET /notes/trash.
container_id
Filter by container.
tag
Filter by tag name.
q
Full-text search within listed notes.
page, per_page
Pagination.
exclude_body
true omits the body field from each note, so sync clients can page through metadata cheaply and fetch full notes one at a time with GET /notes/:id.
GET /api/v1/notes/inbox

Notes without a container. Paginated. Same response shape as listing notes, including exclude_body.

GET /api/v1/notes/:id

Full note with body, tags, container, files, and linked note IDs.

Response example
{
  "id": 1,
  "title": "Weekly review",
  "body": "# Decisions\n\nSee [[42:Project plan]].",
  "summary": "Review of the week",
  "summary_stale": false,
  "source_url": "https://example.com/source",
  "archived": false,
  "favorited": true,
  "position": 1,
  "lock_version": 4,
  "created_at": "2026-03-15T10:00:00Z",
  "updated_at": "2026-03-15T12:30:00Z",
  "tag_list": "review,planning",
  "tags": [
    {"id": 1, "name": "review"},
    {"id": 2, "name": "planning"}
  ],
  "container": {"id": 5, "name": "Work"},
  "files": [
    {
      "id": 10,
      "description": "Slide deck",
      "filename": "slides.pdf",
      "content_type": "application/pdf",
      "byte_size": 204800,
      "url": "https://hjarni.com/rails/active_storage/blobs/..."
    }
  ],
  "linked_note_ids": [42, 58]
}
POST /api/v1/notes

Create a note. Returns 201 on success.

title
Required. Note title.
body
Markdown content. Supports [[id:Title]] wiki-links.
summary
Short summary for quick scanning.
source_url
Canonical source URL.
container_id
Place the note in a container. Omit for inbox.
tag_list
Comma-separated tag names, e.g. "review,planning".
position
Sort position within the container. Omit to leave unpositioned; unpositioned notes sort before positioned ones.
POST /api/v1/notes
{
  "note": {
    "title": "Weekly review",
    "body": "# Weekly review\n\nKey decisions...",
    "summary": "Review of the week",
    "source_url": "https://example.com/source",
    "container_id": 12,
    "tag_list": "review,planning"
  }
}
PATCH /api/v1/notes/:id

Update any note field. Only include the fields you want to change.

PATCH /api/v1/notes/1
{
  "note": {
    "body": "Updated content",
    "tag_list": "review,done"
  }
}

Optional expected_lock_version guards against concurrent edits. Every note read returns a lock_version integer. Echo it back on your write and the server rejects with 409 Conflict if someone else saved in the meantime.

PATCH /api/v1/notes/1
{
  "note": {
    "body": "Updated content",
    "expected_lock_version": 5
  }
}

# 409 Conflict response when the version no longer matches:
{
  "error": "Note was modified since you last read it. Re-read and re-apply...",
  "current_lock_version": 7,
  "last_edited_by": "alice@example.com",
  "last_edited_by_agent": null,
  "last_edited_at": "2026-05-27T14:32:00Z"
}

Surgical body edits are anchor-based and stay safe with or without the version: append_body, replace_find (with replace_with, which deletes the match when omitted), and insert_body (with insert_after or insert_before naming the anchor line). Pass expected_lock_version whenever you also touch non-body fields and want a stale-write guard.

For long notes, prefer the structured patch operations over a full-body replacement — they target a heading or checklist item instead of the whole document, so a stale read can't clobber unrelated sections. Each targets exactly one match and is mutually exclusive with the other body modes.

replace_section + section_body
Replace everything under a heading (with or without leading #), keeping the heading line. The section runs to the next same-or-higher-level heading.
append_to_section + section_body
Add content at the end of a section — the safe way to insert under a heading without knowing its last line.
rename_heading + new_heading
Rename a heading in place. The level is preserved unless new_heading carries its own # markers.
check_item / uncheck_item
Tick or untick a checklist item by its text (e.g. ship it). Matched case- and whitespace-insensitively.
PATCH /api/v1/notes/1
{
  "note": {
    "append_to_section": "## Open Questions",
    "section_body": "- Should we ship Friday?"
  }
}
DELETE /api/v1/notes/:id

Move a note to Trash. Returns 204. The note is recoverable — it stays restorable until it is purged, and can be brought back with POST /notes/:id/restore (see History & Trash below).

Note actions

PATCH /notes/:id/archive

Archive a note. Returns the updated note.

PATCH /notes/:id/unarchive

Restore an archived note. Returns the updated note.

PATCH /notes/:id/favorite

Mark a note as favorited. Returns the updated note.

PATCH /notes/:id/unfavorite

Remove from favorites. Returns the updated note.

PATCH /notes/:id/move

Move to another container. Send {"container_id": 5}.

Note links

POST /notes/:id/link

Link two notes bidirectionally. Send {"target_note_id": 42}. Returns the source note.

DELETE /notes/:id/unlink

Remove the link. Send {"target_note_id": 42}. Returns 204.

GET /notes/:id/linked

List all notes linked to this note. Returns an array of note objects.

Note files

POST /api/v1/notes/:id/files

Attach a file to a note by URL. Hjarni fetches the URL (following redirects) and stores the result. Free accounts can attach up to 20 MB across five personal attachments; uploads beyond that allowance get 403 with an upgrade_url. Returns 201.

url
Required. The file to fetch. Missing or blank returns 422 {"error": "url is required"}.
filename, content_type
Optional overrides; otherwise derived from the URL and response headers.
description
Optional description shown with the attachment.
POST /api/v1/notes/1/files
{"url": "https://example.com/slides.pdf", "description": "Slide deck"}

# 201 response:
{"id": 10, "filename": "slides.pdf", "content_type": "application/pdf",
 "byte_size": 204800, "description": "Slide deck"}

POST /notes and PATCH /notes/:id also accept a nested note_files_attributes array for attaching as part of a create or update.

History & Trash

Every note keeps an append-only revision history, attributed to whoever made each edit (you, an AI agent, or the system). Deletes are recoverable from Trash until they are purged. See Note history and Trash for the concepts behind these endpoints.

GET /notes/:id/history

List revisions, newest first. Each entry carries seq, at, a one-line summary, what changed, and a by block (label, kind, client, agent, source). Accepts limit (1–100, default 50), before_seq for paging, and include_body=true to inline each reconstructed body.

GET /notes/:id/history?seq=N

Reconstruct one revision in full, including its body as it stood at that point.

POST /notes/:id/revert

Revert the note to an earlier revision. Send {"seq": N}. This writes a new revision (it never rewrites history) with reverted_from_seq set. Optional expected_lock_version rejects with 409 Conflict if the note changed since you read it. Returns the updated note.

GET /notes/trash

List trashed notes, most recently deleted first. Each entry adds deleted_at, purge_after, and deleted_by.

POST /notes/:id/restore

Bring a trashed note back. Returns the restored note.

Containers

GET /api/v1/containers

List containers. Paginated. Returns root-level containers by default.

scope
"archived", "all" (all active, flat), or omit for active roots only.
Response example
[
  {
    "id": 5,
    "name": "Work",
    "description": "Day job projects",
    "position": 1,
    "archived": false,
    "llm_instructions": "Use formal tone.",
    "created_at": "2026-03-01T09:00:00Z",
    "updated_at": "2026-03-15T10:00:00Z",
    "notes_count": 12,
    "children_count": 3,
    "parent": null
  }
]
GET /api/v1/containers/:id

Single container with counts and parent info.

POST /api/v1/containers

Create a container. Returns 201.

name
Required. Container name.
description
Optional description.
parent_id
Nest under a parent container. Omit for root.
llm_instructions
AI instructions scoped to this container.
position
Sort position among siblings. Omit to leave unpositioned; unpositioned containers sort before positioned ones.
POST /api/v1/containers
{
  "container": {
    "name": "Research",
    "description": "Papers and reading notes",
    "parent_id": 5
  }
}
PATCH /api/v1/containers/:id

Update name, description, parent, position, or instructions.

DELETE /api/v1/containers/:id

Delete a container. Notes inside it are moved to the inbox. Child containers become root-level. Returns 204.

Container actions

PATCH /containers/:id/archive

Archive. Returns the updated container.

PATCH /containers/:id/unarchive

Restore. Returns the updated container.

GET /containers/:id/children

Direct child containers. Returns an array of container objects.

GET /containers/:id/notes

Notes in this container. Paginated.

GET /containers/:id/tree

Container with its ancestor chain and direct children.

PATCH /containers/reorder

Reorder containers. Send {"ordered_ids": [3,1,2]} with all IDs in the scope. Optional parent_id to reorder children of a specific container. Returns 204.

Root instructions

GET /containers/root_instructions

Get your personal root AI instructions. Returns {"personal_llm_instructions": "..."}.

PATCH /containers/update_root_instructions

Update root instructions. Send {"personal_llm_instructions": "..."}.

Tags

GET /api/v1/tags

List all tags with note counts. Paginated.

Response example
[
  {
    "id": 1,
    "name": "review",
    "created_at": "2026-03-01T09:00:00Z",
    "updated_at": "2026-03-15T10:00:00Z",
    "notes_count": 8
  }
]
GET /api/v1/tags/:id

Single tag with note count.

POST /api/v1/tags

Create a tag. Returns 201.

POST /api/v1/tags
{
  "tag": {"name": "research"}
}
PATCH /api/v1/tags/:id

Rename a tag. Send {"tag": {"name": "new-name"}}.

DELETE /api/v1/tags/:id

Delete a tag. Returns 204. Notes keep their content; only the tag association is removed.

Tag actions

PATCH /tags/:id/merge

Merge this tag into another. Send {"target_id": 5}. All notes are moved to the target tag and this tag is deleted. Returns the target tag.

GET /tags/:id/notes

List notes with this tag. Paginated. Returns note objects.

Errors

401

Missing or invalid token.

403

Two cases. Plan-gated actions (exceeding the Free plan note limit, file uploads beyond the free attachment allowance) return an error message plus upgrade_url. Folder-scoped tokens reaching outside their scope (inbox, tag writes, other folders) return {"error": "Forbidden: outside token scope"} with no upgrade_url.

404

Resource not found or not accessible by your account.

422

Validation failed. Model validations return an errors array with messages; parameter checks (e.g. reorder's ordered_ids, a missing file url) return a single error string.

429

Rate limited: more than 100 requests in a minute on one token. Response is JSON with an error message and a Retry-After header saying when to try again.

Questions about the API?

Email evert@hjarni.com and we'll help.

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