Upsert a comment

POST/api/v2/workspaces/{slug}/projects/{project_id}/work-items/{work_item_id}/comments/upsert/

Comments are the discussion thread on a work item. Create a comment, or update the existing one that carries the same (external_source, external_id) pair.

• Both external_source and external_id are required. Without them there is nothing to match on, and the request returns 400.
• A created record returns 201 with X-Plane-Upsert: created, and an updated one returns 200 with X-Plane-Upsert: updated. Branch on the header instead of guessing from the status.
• Upsert is safe for sequential importers. Two simultaneous upserts of the same key can each miss and each create, so serialize your writes per key.

Path parameters

slug:requiredstring

The workspace slug. It appears in your Plane URLs. In https://app.plane.so/my-team/projects/, the slug is my-team.

project_id:requiredstring

The project the resource belongs to. Accepts the project UUID or its bare identifier, for example ENG.

work_item_id:requiredstring

The work item the resource belongs to. Accepts the work item UUID or its PROJ-123 identifier.

Body parameters

comment_html:requiredstring

The comment body, as HTML.

access:optionalstring

Visibility of the comment. One of INTERNAL, EXTERNAL.

parent_id:optionalstring (uuid)

Make the comment a reply to this comment. The parent must be a top-level comment on the same work item, and a reply takes its parent's access. Send null for a top-level comment.

Nullable.

external_id:optionalstring

Your system's identifier for this record, for sync and import correlation.

Maximum 255 characters. Nullable.

external_source:optionalstring

The system external_id came from, for example github or jira.

Maximum 255 characters. Nullable.

Response shaping

fields:optionalstring

Comma-separated list of fields to return. Fields you don't request are left out of the response instead of coming back as null. id is always included. Pass all to get every requestable field. An unknown field name returns 400. See Sparse fields.

Requestable here: access, actor_id, comment_html, comment_stripped, created_at, created_by_id, edited_at, external_id, external_source, hidden_at, hidden_by_id, hidden_reason, id, parent_id, updated_at, updated_by_id, work_item_id.

expand:optionalstring

Comma-separated relations to embed: actor.

Expanded objects get their own key: ?expand=state keeps state_id and adds a state object next to it. ?fields= and ?expand= work independently. Naming a relation in ?fields= returns 400, and field filtering never removes an expanded object. See Expanding relations.

Scopes

projects.work_items.comments:write

Errors

Status	Code	Cause
400	invalid_request	The request body or a query parameter failed validation.
401	unauthorized	Missing or invalid credentials.
402	payment_required	The feature this endpoint belongs to isn't enabled on your plan or is switched off.
403	forbidden	Your role or token scope doesn't allow this.
404	not_found	No such resource, or it's outside your tenant.
406	not_acceptable	The Accept header asks for a representation the API can't produce.
409	conflict	A business rule blocks the write.
413	payload_too_large	The request body is over the size limit.
415	unsupported_media_type	The Content-Type isn't one this endpoint accepts.
429	rate_limited	Throttled. Honor the Retry-After header before retrying.

Upsert a comment

curl -X POST \
  "https://api.plane.so/api/v2/workspaces/my-team/projects/4af68566-94a4-4eb3-94aa-50dc9427067b/work-items/9c1f0b3d-6d2e-4c9a-8b41-2f7e5a0d6c88/comments/upsert/" \
  -H "X-Api-Key: $PLANE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "comment_html": "<p>Customer confirmed the fix on their account.</p>",
  "parent_id": "e5b2c8a1-7d34-4f9e-a0c6-2b8d1f5e3a97",
  "external_source": "zendesk",
  "external_id": "ZD-88431"
}'

import requests

response = requests.post(
    "https://api.plane.so/api/v2/workspaces/my-team/projects/4af68566-94a4-4eb3-94aa-50dc9427067b/work-items/9c1f0b3d-6d2e-4c9a-8b41-2f7e5a0d6c88/comments/upsert/",
    headers={"X-Api-Key": "your-api-key"},
    json={
        "comment_html": "<p>Customer confirmed the fix on their account.</p>",
        "parent_id": "e5b2c8a1-7d34-4f9e-a0c6-2b8d1f5e3a97",
        "external_source": "zendesk",
        "external_id": "ZD-88431",
    },
)
print(response.headers["X-Plane-Upsert"], response.json())

const response = await fetch(
  "https://api.plane.so/api/v2/workspaces/my-team/projects/4af68566-94a4-4eb3-94aa-50dc9427067b/work-items/9c1f0b3d-6d2e-4c9a-8b41-2f7e5a0d6c88/comments/upsert/",
  {
    method: "POST",
    headers: {
      "X-Api-Key": "your-api-key",
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      comment_html: "<p>Customer confirmed the fix on their account.</p>",
      parent_id: "e5b2c8a1-7d34-4f9e-a0c6-2b8d1f5e3a97",
      external_source: "zendesk",
      external_id: "ZD-88431",
    }),
  },
);
const data = await response.json();

Response200

{
  "id": "b7e42a19-3c5d-4f80-9a26-8d1c0f4e7b53",
  "work_item_id": "9c1f0b3d-6d2e-4c9a-8b41-2f7e5a0d6c88",
  "parent_id": "e5b2c8a1-7d34-4f9e-a0c6-2b8d1f5e3a97",
  "comment_html": "<p>Customer confirmed the fix on their account.</p>",
  "comment_stripped": "Customer confirmed the fix on their account.",
  "access": "EXTERNAL",
  "actor_id": "16c61a3a-512a-48ac-b0be-b6b46fe6f430",
  "external_id": "ZD-88431",
  "external_source": "zendesk",
  "edited_at": "2026-01-16T09:41:27.553018Z",
  "hidden_at": null,
  "hidden_by_id": null,
  "hidden_reason": null,
  "created_at": "2026-01-15T17:20:03.118462Z",
  "updated_at": "2026-01-16T09:41:27.556204Z",
  "created_by_id": "16c61a3a-512a-48ac-b0be-b6b46fe6f430",
  "updated_by_id": "16c61a3a-512a-48ac-b0be-b6b46fe6f430"
}