# List change history

> What has happened to the workspace's plants or explants, oldest first: transfers, stage changes, contamination records, observations, printed labels.

Source: https://docs.xplantpro.com/docs/api/change-history/list-change-events

`GET https://app.xplantpro.com/api/v1/events`

- Required scope: `read:events`
- Credentials: workspace API key (`xpk_`)
- Idempotency-Key: ignored on this endpoint

Use it to keep your own system in step with xPlant without downloading everything again:

1. The first time, call with `entity=plant` and follow `meta.next_cursor` until it comes back `null`. Do the same with `entity=explant`.
2. Save the newest `created_at` you received for each.
3. Next time, pass that value as `since` and follow the cursor again from the first page.

Several events can share one `created_at` — a batch import records many at once. The cursor keeps them in a fixed order, so a walk neither skips nor repeats one; still walk a `since` window to its last page before you move `since` forward, and skip any `id` you already hold.

The history is written by work done in xPlant. Transfers and stage moves recorded through this API's own endpoints do not add events here; their responses already carry what was saved.

See also: [Pull change history](https://docs.xplantpro.com/docs/guides/change-history.md).

## Query parameters

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| `entity` | `"plant"` \| `"explant"` | Yes | Which history to read. Required: plant and explant histories are separate, so sync each with its own calls. |
| `since` | string | No | Only events recorded after this moment, as an ISO 8601 timestamp such as `2026-09-24T00:00:00Z`. Pass the newest `created_at` you already hold. |
| `limit` | integer | No | Page size. Values above 200 are capped at 200. Default `50`. From 1 to 200. |
| `offset` | integer | No | Number of records to skip. Prefer `cursor` where a list offers it: an offset shifts when records are added ahead of it. Default `0`. At least 0. |
| `cursor` | string | No | Continue from the previous page: pass its `meta.next_cursor` unchanged, with the same filters. Treat it as opaque. Not combinable with `offset`. Up to 2048 characters. |

## Example

**curl**

```bash
curl "https://app.xplantpro.com/api/v1/events?entity=plant&since=2026-09-01T00%3A00%3A00Z" \
  -H "Authorization: Bearer $XPLANT_API_KEY"
```

**JavaScript**

```js
import { XPlantClient } from "@shmaplex/xplant-sdk";

const client = new XPlantClient({ apiKey: process.env.XPLANT_API_KEY });

const events = await client.events.list({ entity: "plant", since: "2026-09-01T00:00:00Z" });
```

**Python**

```python
import os
import requests

resp = requests.get(
    "https://app.xplantpro.com/api/v1/events",
    headers={"Authorization": f"Bearer {os.environ['XPLANT_API_KEY']}"},
    params={"entity": "plant", "since": "2026-09-01T00:00:00Z"},
    timeout=10,
)
body = resp.json()
if not body["ok"]:
    raise RuntimeError(f"{resp.status_code} {body['code']}: {body['error']}")
events = body["data"]
```

## Response

`200` with `{ "ok": true, "data": … }`. `data` is an array. To get the next page, pass `meta.next_cursor` back as `cursor`; it is `null` on the last page. See [Pagination](https://docs.xplantpro.com/docs/pagination.md).

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `id` | string (uuid) | Yes | The event's id. Events are never edited, so an id you already hold is the same event. |
| `entity_type` | `"plant"` \| `"explant"` | Yes | Whether the event is about a plant or an explant. |
| `entity_id` | string (uuid) | Yes | The plant's or explant's id. |
| `stage_id` | string \| null (uuid) | Yes | The stage the event was recorded against, when there was one. |
| `event_type` | string | Yes | What happened — for example `transfer`, `stage_change`, `contamination`, `observation` or `label_print`. New kinds can appear; treat one you do not recognise as informational. |
| `event_time` | string | Yes | When it happened in the lab, as an ISO 8601 timestamp. |
| `recorded_by` | string \| null (uuid) | Yes | The workspace member who recorded it, when known. |
| `payload` | any | Yes | The event's details, as a JSON value whose fields depend on `event_type` — a transfer, for example, carries its cycle, locations and vessel counts. Can be null. |
| `created_at` | string | Yes | When xPlant recorded the event. Pass the newest one you hold back as `since`. |

```json title="Response"
{
  "ok": true,
  "data": [
    {
      "id": "4b3a2918-0716-4f5e-8d4c-3b2a19087f6e",
      "entity_type": "explant",
      "entity_id": "a1b2c3d4-e5f6-4a7b-8c9d-0e1f2a3b4c5d",
      "stage_id": "6e5d4c3b-2a19-4807-96a5-b4c3d2e1f0a9",
      "event_type": "transfer",
      "event_time": "2026-09-24T00:00:00+00:00",
      "recorded_by": "0d7e4b9a-6f21-4c3e-8a5b-2e9f1c7d4a60",
      "payload": {
        "transfer_id": "c7d8e9f0-a1b2-4c3d-8e4f-5a6b7c8d9e0f",
        "transfer_cycle": 5,
        "from_location": "Growth room 1, shelf B2",
        "to_location": "Growth room 1, shelf C1",
        "observed_vessel_count": 12,
        "plantlet_count": 48
      },
      "created_at": "2026-09-24T09:12:45.118Z"
    }
  ]
}
```

The envelope can also carry `meta`:

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `next_cursor` | string \| null | Yes | Pass as `cursor` to fetch the next page. `null` means this is the last page. |

| Response header | Meaning |
| --- | --- |
| `X-Request-Id` | Identifies this request. Include it when you contact support. |

## Errors

| Status | Code | When |
| --- | --- | --- |
| `401` | `UNAUTHORIZED` | The key is missing, malformed or revoked, or its owner is no longer a member of the workspace. |
| `402` | `PAID_PLAN_REQUIRED` | The workspace's plan does not include the API. The full API is included with xPlant+ Teams and Enterprise; on Hobby and Pro Lab, keys can connect devices only. |
| `403` | `FORBIDDEN` | The key lacks a scope this operation requires, or its owner's current role in the workspace cannot use it — a key never does more than its owner can in xPlant. `error` names the scope, and for a role, the role it needs. |
| `403` | `DEVICE_TOKEN_NOT_ACCEPTED` | A device token was sent; this operation needs a workspace API key. |
| `422` | `VALIDATION_ERROR` | Both `cursor` and `offset` were sent; use one. |
| `422` | `INVALID_CURSOR` | The cursor is malformed, or came from a different list or different filters. Start again without it. |
| `422` | `VALIDATION_ERROR` | `entity` is missing or is not `plant` or `explant`, or `since` is not a valid timestamp. |
| `429` | `RATE_LIMIT_EXCEEDED` | Too many requests for this key, device token or workspace. Wait `Retry-After` seconds. |
| `500` | `EVENT_QUERY_FAILED` | The history could not be read. Retry later. |

Branch on `code`, never on the `error` text. See [Errors](https://docs.xplantpro.com/docs/errors.md).