# Advance a stage

> Moves a plant or explant into a new stage in one call: the stage it is in now is marked completed, the new one is recorded, and it becomes the current stage. Send exactly one of plant_id or explant_id.

Source: https://docs.xplantpro.com/docs/api/transfers-and-stages/create-stage

`POST https://app.xplantpro.com/api/v1/stages`

- Required scope: `write:transfers`
- Credentials: workspace API key (`xpk_`)
- Idempotency-Key: honoured (24 hours)

`stage` is checked against your lab's own stage list for plants or for explants, whichever you are moving, the same way xPlant checks it. A stage's older display name is saved as its key, so the response carries the key you should send next time. A name your lab does not use is refused before anything changes.

A key can move the plants and explants its owner created. Moving a teammate's needs the key's owner to be a manager or owner of the lab, as it does in xPlant.

The move is added to the plant's or explant's history: `GET /api/v1/events` returns it as a `stage_change` event.

Every successful move answers with `meta` beside the stage: `meta.previous_stage_id` names the stage that was closed, so your system can mirror the change without reading the history back. Send an `Idempotency-Key` when you might retry: a repeated move would otherwise close the stage the first attempt opened.

Send an `Idempotency-Key` header to make retries safe: a repeat with the same key within 24 hours returns the first response instead of writing twice. See [Idempotency](https://docs.xplantpro.com/docs/idempotency.md).

## Headers

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| `Idempotency-Key` | string | No | Any unique string you choose per logical write. A retry carrying the same key within 24 hours returns the first result instead of writing again. Scoped to your API key and this operation. 8–255 characters. Must match `^[A-Za-z0-9._:~-]+$`. |

## Request body

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `plant_id` | string (uuid) | No | The plant this is for. Send exactly one of `plant_id` or `explant_id`. |
| `explant_id` | string (uuid) | No | The explant this is for. Send exactly one of `plant_id` or `explant_id`. |
| `stage` | string | Yes | The stage to move into, as a key from your lab's stage list. Plants and explants have separate lists — for example `multiplication` or `root_induction` for an explant, `production` for a plant. A stage's older display name, such as `Multiplication`, is accepted and saved as its key. A name your lab does not use is refused. 1–50 characters. |
| `entered_on` | string | No | When it entered the stage: a date such as `2026-09-24`, or a full ISO 8601 timestamp. Defaults to today (UTC). |
| `room_id` | string (uuid) | No | The growing room it is in for this stage. Must be a room in the workspace. |
| `notes` | string | No | Up to 5000 characters. |

## Example

**curl**

```bash
curl -X POST https://app.xplantpro.com/api/v1/stages \
  -H "Authorization: Bearer $XPLANT_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "explant_id": "a1b2c3d4-e5f6-4a7b-8c9d-0e1f2a3b4c5d",
    "stage": "multiplication",
    "entered_on": "2026-09-24",
    "notes": "Shoot clusters forming well on the Alocasia line."
  }'
```

**JavaScript**

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

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

const stage = await client.stages.advance({
  explant_id: "a1b2c3d4-e5f6-4a7b-8c9d-0e1f2a3b4c5d",
  stage: "multiplication",
  entered_on: "2026-09-24",
  notes: "Shoot clusters forming well on the Alocasia line.",
});
```

**Python**

```python
import os
import requests

resp = requests.post(
    "https://app.xplantpro.com/api/v1/stages",
    headers={"Authorization": f"Bearer {os.environ['XPLANT_API_KEY']}"},
    json={
        "explant_id": "a1b2c3d4-e5f6-4a7b-8c9d-0e1f2a3b4c5d",
        "stage": "multiplication",
        "entered_on": "2026-09-24",
        "notes": "Shoot clusters forming well on the Alocasia line.",
    },
    timeout=10,
)
body = resp.json()
if not body["ok"]:
    raise RuntimeError(f"{resp.status_code} {body['code']}: {body['error']}")
stage = body["data"]
```

## Response

`201` with `{ "ok": true, "data": … }`. `data` holds the result.

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `id` | string (uuid) | Yes | — |
| `entity_type` | `"plant"` \| `"explant"` | Yes | Whether the stage belongs to a plant or an explant. |
| `entity_id` | string (uuid) | Yes | The plant's or explant's id. |
| `stage` | string | Yes | The stage, as a key from your lab's stage list such as `multiplication`. Records made by older tools can carry the stage's display name instead, such as `Multiplication`. |
| `status` | string | Yes | `active` for the stage the plant or explant is in now, `completed` for one it has moved on from. Stages can also be `failed` or `archived`. |
| `entered_on` | string \| null | Yes | When it entered this stage, as an ISO 8601 timestamp. |
| `completed_at` | string \| null | Yes | When it moved on from this stage. Null while the stage is current. |
| `room_id` | string \| null (uuid) | Yes | The room it was in for this stage, when one was recorded. |
| `notes` | string \| null | Yes | — |
| `created_at` | string \| null | Yes | — |

```json title="Response"
{
  "ok": true,
  "data": {
    "id": "6e5d4c3b-2a19-4807-96a5-b4c3d2e1f0a9",
    "entity_type": "explant",
    "entity_id": "a1b2c3d4-e5f6-4a7b-8c9d-0e1f2a3b4c5d",
    "stage": "multiplication",
    "status": "active",
    "entered_on": "2026-09-24T00:00:00+00:00",
    "completed_at": null,
    "room_id": null,
    "notes": "Shoot clusters forming well on the Alocasia line.",
    "created_at": "2026-09-24T08:41:17.000Z"
  }
}
```

The envelope can also carry `meta`:

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `previous_stage_id` | string \| null (uuid) | No | The stage this one replaced, which is now `completed`. Null when there was no current stage. |
| `warning` | string | No | Sent instead of `previous_stage_id` when the stage was saved but could not be made the current one. The history is complete; set the current stage in xPlant. |

| Response header | Meaning |
| --- | --- |
| `Idempotent-Replay` | `true` when this response is a replay of an earlier request with the same `Idempotency-Key`. |
| `X-Request-Id` | Identifies this request. Include it when you contact support. |

## Errors

| Status | Code | When |
| --- | --- | --- |
| `400` | `VALIDATION_ERROR` | The request body is not valid JSON. |
| `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. |
| `403` | `STAGE_WRITE_FORBIDDEN` | The plant or explant was created by someone else, and the key's owner is not a manager or owner of the lab. Nothing was changed. |
| `404` | `NOT_FOUND` | The plant or explant, or the growing room named in `room_id`, is not in this workspace. Nothing was changed. |
| `409` | `IDEMPOTENCY_IN_FLIGHT` | A request with this `Idempotency-Key` is still being processed; retry after `Retry-After` seconds. |
| `422` | `VALIDATION_ERROR` | The `Idempotency-Key` header is malformed. |
| `422` | `VALIDATION_ERROR` | A field failed validation, or neither or both of `plant_id` and `explant_id` were sent. `error` names the first problem, for example `stage: stage is required`. |
| `422` | `VALIDATION_ERROR` | `stage` is not in your lab's stage list for a plant, or for an explant — whichever you sent. `error` starts `stage:` and names the list. Nothing was changed. |
| `429` | `RATE_LIMIT_EXCEEDED` | Too many requests for this key, device token or workspace. Wait `Retry-After` seconds. |
| `500` | `STAGE_ADVANCE_FAILED` | The stage could not be saved. Retry with the same `Idempotency-Key`. |

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