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 is a 400.
• A created record answers 201 with X-Plane-Upsert: created; an updated one answers 200 with X-Plane-Upsert: updated. Branch on the header rather than 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 hangs off. Accepts the work item UUID or its PROJ-123 identifier.

Body Parameters

comment_html:requiredstring

The comment html.

access:optionalstring

• INTERNAL - INTERNAL
• EXTERNAL - EXTERNAL

One of INTERNAL, EXTERNAL.

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. Unrequested keys are omitted, not returned as null. id always comes back. Pass all for every requestable field. An unknown name is a 400. See Sparse fields.

Requestable here: access, actor_id, comment_html, comment_stripped, created_at, created_by_id, edited_at, external_id, external_source, id, work_item_id.

expand:optionalstring

Comma-separated relations to embed: actor.

Expansion is separate-key — ?expand=state keeps state_id and adds a state object next to it. ?fields= and ?expand= are independent: naming a relation in ?fields= is a 400, and expanded objects survive field filtering. 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 — see the notes above.
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": "example",
  "access": "INTERNAL",
  "external_id": null,
  "external_source": null
}'

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": "example",
        "access": "INTERNAL",
        "external_id": None,
        "external_source": None
    },
)
print(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: "example",
      access: "INTERNAL",
      external_id: null,
      external_source: null,
    }),
  },
);
const data = await response.json();

Response200

{
  "access": "INTERNAL",
  "actor_id": "f960d3c2-8524-4a41-b8eb-055ce4be2a7f",
  "comment_html": "example",
  "comment_stripped": "example",
  "created_at": "2026-01-14T09:22:41.478363Z",
  "created_by_id": "16c61a3a-512a-48ac-b0be-b6b46fe6f430",
  "edited_at": "2026-01-14T09:22:41.478363Z",
  "external_id": null,
  "external_source": null,
  "id": "b7e42a19-3c5d-4f80-9a26-8d1c0f4e7b53",
  "work_item_id": "f960d3c2-8524-4a41-b8eb-055ce4be2a7f"
}