List a model's instances

Lists the instances serving a model you own, grouped by cluster. Only the production environment’s instances are listed. The CLI equivalent is reactor model instances.

By default only live instances are returned. With alive_only=false, the response also includes instances that served a session in a time window of at most 7 days, paged with limit and cursor. Live instances and their counts appear on the first page only. An instance from history can appear on more than one page: merge pods by (cluster_id, machine_id) and keep the newest last_session_at.

Callable by an account_admin or developer of the owning account. Another account’s model returns 403, or 404 if it is public.

GET

models

{id}

instances

List a model's instances

curl --request GET \
  --url https://api.reactor.inc/models/{id}/instances \
  --header 'Authorization: Bearer <token>'

const options = {method: 'GET', headers: {Authorization: 'Bearer <token>'}};

fetch('https://api.reactor.inc/models/{id}/instances', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.reactor.inc/models/{id}/instances",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "GET",
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"net/http"
	"io"
)

func main() {

	url := "https://api.reactor.inc/models/{id}/instances"

	req, _ := http.NewRequest("GET", url, nil)

	req.Header.Add("Authorization", "Bearer <token>")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

require 'uri'
require 'net/http'

url = URI("https://api.reactor.inc/models/{id}/instances")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Get.new(url)
request["Authorization"] = 'Bearer <token>'

response = http.request(request)
puts response.read_body

{
  "model_id": "7b3f1bc2-a4e5-4d78-b9c1-0e6c2f9a1d34",
  "model": "your-org/your-model",
  "instances": [
    {
      "cluster_id": "d2c3911b-6acc-4fe5-81eb-b06235963615",
      "cluster": "us-east-2.prod.reactor.inc",
      "zone": "us-east-2a",
      "region": "us-east",
      "counts": {
        "desired": 2,
        "running": 2,
        "healthy": 2,
        "initializing": 0,
        "idle": 1
      },
      "pods": [
        {
          "machine_id": "your-model-7f9c-x2k",
          "alive": true,
          "status": "healthy",
          "last_session_at": "2026-11-03T22:01:10Z"
        },
        {
          "machine_id": "your-model-5d2a-p8q",
          "alive": true,
          "status": "healthy"
        }
      ]
    }
  ],
  "count": 2
}

{
  "error": "<string>",
  "message": "<string>",
  "resource": "<string>",
  "reason": "<string>"
}

{
  "error": "<string>",
  "message": "<string>",
  "resource": "<string>",
  "reason": "<string>"
}

{
  "error": "<string>",
  "message": "<string>",
  "resource": "<string>",
  "reason": "<string>"
}

{
  "error": "<string>",
  "message": "<string>",
  "resource": "<string>",
  "reason": "<string>"
}

{
  "error": "<string>",
  "message": "<string>",
  "resource": "<string>",
  "reason": "<string>"
}

Authorizations

Authorization

string

header

required

A Reactor API key (rk_...), sent as Authorization: Bearer rk_.... Keep it on a server.

Path Parameters

string<uuid>

required

The model's ID (not its project ID). Find it with GET /models?name=your-org/your-model.

Query Parameters

alive_only

boolean

default:true

true returns live instances only and ignores the window and paging parameters. false adds instances that served a session in the window.

start

string<date-time>

Inclusive start of the history window, RFC 3339. Defaults to 24 hours before end. Only with alive_only=false.

end

string<date-time>

Exclusive end of the history window, RFC 3339. Defaults to now. Only with alive_only=false.

since

string

A window ending now, as a duration such as 24h or 7d. Cannot be combined with start or end. Only with alive_only=false.

Example:

"24h"

limit

integer

default:200

Maximum session-history rows read for the page (not the number of instances returned). Only with alive_only=false.

Required range: 1 <= x <= 200

cursor

string

The next_cursor of the previous page. Only with alive_only=false.

Response

The model's instances.

model_id

string<uuid>

required

model

string

required

Example:

"your-org/your-model"

instances

object[]

required

Show child attributes

count

integer

required

Instances in this response, not a total across pages.

next_cursor

string

Present when another history page exists.

⌘I

List a model's instances

curl --request GET \
  --url https://api.reactor.inc/models/{id}/instances \
  --header 'Authorization: Bearer <token>'

const options = {method: 'GET', headers: {Authorization: 'Bearer <token>'}};

fetch('https://api.reactor.inc/models/{id}/instances', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.reactor.inc/models/{id}/instances",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "GET",
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"net/http"
	"io"
)

func main() {

	url := "https://api.reactor.inc/models/{id}/instances"

	req, _ := http.NewRequest("GET", url, nil)

	req.Header.Add("Authorization", "Bearer <token>")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

require 'uri'
require 'net/http'

url = URI("https://api.reactor.inc/models/{id}/instances")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Get.new(url)
request["Authorization"] = 'Bearer <token>'

response = http.request(request)
puts response.read_body

{
  "model_id": "7b3f1bc2-a4e5-4d78-b9c1-0e6c2f9a1d34",
  "model": "your-org/your-model",
  "instances": [
    {
      "cluster_id": "d2c3911b-6acc-4fe5-81eb-b06235963615",
      "cluster": "us-east-2.prod.reactor.inc",
      "zone": "us-east-2a",
      "region": "us-east",
      "counts": {
        "desired": 2,
        "running": 2,
        "healthy": 2,
        "initializing": 0,
        "idle": 1
      },
      "pods": [
        {
          "machine_id": "your-model-7f9c-x2k",
          "alive": true,
          "status": "healthy",
          "last_session_at": "2026-11-03T22:01:10Z"
        },
        {
          "machine_id": "your-model-5d2a-p8q",
          "alive": true,
          "status": "healthy"
        }
      ]
    }
  ],
  "count": 2
}

{
  "error": "<string>",
  "message": "<string>",
  "resource": "<string>",
  "reason": "<string>"
}

{
  "error": "<string>",
  "message": "<string>",
  "resource": "<string>",
  "reason": "<string>"
}

{
  "error": "<string>",
  "message": "<string>",
  "resource": "<string>",
  "reason": "<string>"
}

{
  "error": "<string>",
  "message": "<string>",
  "resource": "<string>",
  "reason": "<string>"
}

{
  "error": "<string>",
  "message": "<string>",
  "resource": "<string>",
  "reason": "<string>"
}

Get started

SDK Reference

CLI Reference

Platform API Reference

Endpoints

List a model's instances

Authorizations

Path Parameters

Query Parameters

Response