curl --request PUT \
  --url https://app.launchdarkly.com/api/v2/projects/{projectKey}/flags/{flagKey}/release/phases/{phaseId} \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "status": "Started",
  "audiences": [
    {
      "audienceId": "<string>",
      "releaseGuardianConfiguration": {
        "monitoringWindowMilliseconds": 60000,
        "rolloutWeight": 50,
        "rollbackOnRegression": true,
        "randomizationUnit": "user"
      },
      "notifyMemberIds": [
        "1234a56b7c89d012345e678f"
      ],
      "notifyTeamKeys": [
        "example-reviewer-team"
      ]
    }
  ]
}
'

import requests

url = "https://app.launchdarkly.com/api/v2/projects/{projectKey}/flags/{flagKey}/release/phases/{phaseId}"

payload = {
    "status": "Started",
    "audiences": [
        {
            "audienceId": "<string>",
            "releaseGuardianConfiguration": {
                "monitoringWindowMilliseconds": 60000,
                "rolloutWeight": 50,
                "rollbackOnRegression": True,
                "randomizationUnit": "user"
            },
            "notifyMemberIds": ["1234a56b7c89d012345e678f"],
            "notifyTeamKeys": ["example-reviewer-team"]
        }
    ]
}
headers = {
    "Authorization": "<api-key>",
    "Content-Type": "application/json"
}

response = requests.put(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'PUT',
  headers: {Authorization: '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    status: 'Started',
    audiences: [
      {
        audienceId: '<string>',
        releaseGuardianConfiguration: {
          monitoringWindowMilliseconds: 60000,
          rolloutWeight: 50,
          rollbackOnRegression: true,
          randomizationUnit: 'user'
        },
        notifyMemberIds: ['1234a56b7c89d012345e678f'],
        notifyTeamKeys: ['example-reviewer-team']
      }
    ]
  })
};

fetch('https://app.launchdarkly.com/api/v2/projects/{projectKey}/flags/{flagKey}/release/phases/{phaseId}', 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://app.launchdarkly.com/api/v2/projects/{projectKey}/flags/{flagKey}/release/phases/{phaseId}",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "PUT",
  CURLOPT_POSTFIELDS => json_encode([
    'status' => 'Started',
    'audiences' => [
        [
                'audienceId' => '<string>',
                'releaseGuardianConfiguration' => [
                                'monitoringWindowMilliseconds' => 60000,
                                'rolloutWeight' => 50,
                                'rollbackOnRegression' => true,
                                'randomizationUnit' => 'user'
                ],
                'notifyMemberIds' => [
                                '1234a56b7c89d012345e678f'
                ],
                'notifyTeamKeys' => [
                                'example-reviewer-team'
                ]
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: <api-key>",
    "Content-Type: application/json"
  ],
]);

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

curl_close($curl);

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

package main

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

func main() {

	url := "https://app.launchdarkly.com/api/v2/projects/{projectKey}/flags/{flagKey}/release/phases/{phaseId}"

	payload := strings.NewReader("{\n  \"status\": \"Started\",\n  \"audiences\": [\n    {\n      \"audienceId\": \"<string>\",\n      \"releaseGuardianConfiguration\": {\n        \"monitoringWindowMilliseconds\": 60000,\n        \"rolloutWeight\": 50,\n        \"rollbackOnRegression\": true,\n        \"randomizationUnit\": \"user\"\n      },\n      \"notifyMemberIds\": [\n        \"1234a56b7c89d012345e678f\"\n      ],\n      \"notifyTeamKeys\": [\n        \"example-reviewer-team\"\n      ]\n    }\n  ]\n}")

	req, _ := http.NewRequest("PUT", url, payload)

	req.Header.Add("Authorization", "<api-key>")
	req.Header.Add("Content-Type", "application/json")

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

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

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.put("https://app.launchdarkly.com/api/v2/projects/{projectKey}/flags/{flagKey}/release/phases/{phaseId}")
  .header("Authorization", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"status\": \"Started\",\n  \"audiences\": [\n    {\n      \"audienceId\": \"<string>\",\n      \"releaseGuardianConfiguration\": {\n        \"monitoringWindowMilliseconds\": 60000,\n        \"rolloutWeight\": 50,\n        \"rollbackOnRegression\": true,\n        \"randomizationUnit\": \"user\"\n      },\n      \"notifyMemberIds\": [\n        \"1234a56b7c89d012345e678f\"\n      ],\n      \"notifyTeamKeys\": [\n        \"example-reviewer-team\"\n      ]\n    }\n  ]\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://app.launchdarkly.com/api/v2/projects/{projectKey}/flags/{flagKey}/release/phases/{phaseId}")

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

request = Net::HTTP::Put.new(url)
request["Authorization"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"status\": \"Started\",\n  \"audiences\": [\n    {\n      \"audienceId\": \"<string>\",\n      \"releaseGuardianConfiguration\": {\n        \"monitoringWindowMilliseconds\": 60000,\n        \"rolloutWeight\": 50,\n        \"rollbackOnRegression\": true,\n        \"randomizationUnit\": \"user\"\n      },\n      \"notifyMemberIds\": [\n        \"1234a56b7c89d012345e678f\"\n      ],\n      \"notifyTeamKeys\": [\n        \"example-reviewer-team\"\n      ]\n    }\n  ]\n}"

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

{
  "name": "Example release pipeline",
  "releasePipelineKey": "example-release-pipeline",
  "releasePipelineDescription": "Our release pipeline for typical testing and deployment",
  "phases": [
    {
      "_id": "1234a56b7c89d012345e678f",
      "_name": "Phase 1 - Testing",
      "complete": true,
      "_creationDate": "1684262711507",
      "_audiences": [
        {
          "_id": "1234a56b7c89d012345e678g",
          "name": "Phase 1 - Testing",
          "_links": {},
          "environment": {
            "_links": {
              "self": {
                "href": "/api/v2/projects/my-project/environments/my-environment",
                "type": "application/json"
              }
            },
            "key": "environment-key-123abc",
            "name": "My Environment",
            "color": "F5A623"
          },
          "configuration": {
            "releaseStrategy": "monitoredRelease",
            "requireApproval": true,
            "notifyMemberIds": [
              "1234a56b7c89d012345e678f"
            ],
            "notifyTeamKeys": [
              "example-reviewer-team"
            ],
            "releaseGuardianConfiguration": {
              "monitoringWindowMilliseconds": 60000,
              "rolloutWeight": 50,
              "rollbackOnRegression": true,
              "randomizationUnit": "user"
            }
          },
          "segmentKeys": [
            "segment-key-123abc"
          ],
          "status": "active",
          "_ruleIds": [
            "<string>"
          ]
        }
      ],
      "_completionDate": "1684262711509",
      "_completedBy": {
        "member": {
          "_links": {
            "self": {
              "href": "/api/v2/members/569f183514f4432160000007",
              "type": "application/json"
            }
          },
          "_id": "569f183514f4432160000007",
          "role": "admin",
          "email": "ariel@acme.com",
          "firstName": "Ariel",
          "lastName": "Flores"
        },
        "token": {
          "_links": {},
          "_id": "<string>",
          "name": "DevOps token",
          "ending": "2345",
          "serviceToken": false
        }
      },
      "status": "Started",
      "started": true,
      "_startedDate": 123,
      "configuration": {}
    }
  ],
  "_version": 1,
  "_links": {},
  "_releaseVariationId": "<string>",
  "_canceledAt": "1684262711507"
}

{
  "code": "invalid_request",
  "message": "Invalid request body"
}

{
  "code": "unauthorized",
  "message": "Invalid access token"
}

{
  "code": "not_found",
  "message": "Invalid resource identifier"
}

{
  "code": "rate_limited",
  "message": "You've exceeded the API rate limit. Try again later."
}