curl --request PUT \
  --url https://app.launchdarkly.com/api/v2/projects/{projectKey}/flag-defaults \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "tags": [
    "tag-1",
    "tag-2"
  ],
  "temporary": true,
  "booleanDefaults": {
    "trueDisplayName": "True",
    "falseDisplayName": "False",
    "trueDescription": "serve true",
    "falseDescription": "serve false",
    "onVariation": 0,
    "offVariation": 1
  },
  "defaultClientSideAvailability": {
    "usingMobileKey": true,
    "usingEnvironmentId": true
  }
}
'

import requests

url = "https://app.launchdarkly.com/api/v2/projects/{projectKey}/flag-defaults"

payload = {
    "tags": ["tag-1", "tag-2"],
    "temporary": True,
    "booleanDefaults": {
        "trueDisplayName": "True",
        "falseDisplayName": "False",
        "trueDescription": "serve true",
        "falseDescription": "serve false",
        "onVariation": 0,
        "offVariation": 1
    },
    "defaultClientSideAvailability": {
        "usingMobileKey": True,
        "usingEnvironmentId": True
    }
}
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({
    tags: ['tag-1', 'tag-2'],
    temporary: true,
    booleanDefaults: {
      trueDisplayName: 'True',
      falseDisplayName: 'False',
      trueDescription: 'serve true',
      falseDescription: 'serve false',
      onVariation: 0,
      offVariation: 1
    },
    defaultClientSideAvailability: {usingMobileKey: true, usingEnvironmentId: true}
  })
};

fetch('https://app.launchdarkly.com/api/v2/projects/{projectKey}/flag-defaults', 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}/flag-defaults",
  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([
    'tags' => [
        'tag-1',
        'tag-2'
    ],
    'temporary' => true,
    'booleanDefaults' => [
        'trueDisplayName' => 'True',
        'falseDisplayName' => 'False',
        'trueDescription' => 'serve true',
        'falseDescription' => 'serve false',
        'onVariation' => 0,
        'offVariation' => 1
    ],
    'defaultClientSideAvailability' => [
        'usingMobileKey' => true,
        'usingEnvironmentId' => true
    ]
  ]),
  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}/flag-defaults"

	payload := strings.NewReader("{\n  \"tags\": [\n    \"tag-1\",\n    \"tag-2\"\n  ],\n  \"temporary\": true,\n  \"booleanDefaults\": {\n    \"trueDisplayName\": \"True\",\n    \"falseDisplayName\": \"False\",\n    \"trueDescription\": \"serve true\",\n    \"falseDescription\": \"serve false\",\n    \"onVariation\": 0,\n    \"offVariation\": 1\n  },\n  \"defaultClientSideAvailability\": {\n    \"usingMobileKey\": true,\n    \"usingEnvironmentId\": true\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}/flag-defaults")
  .header("Authorization", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"tags\": [\n    \"tag-1\",\n    \"tag-2\"\n  ],\n  \"temporary\": true,\n  \"booleanDefaults\": {\n    \"trueDisplayName\": \"True\",\n    \"falseDisplayName\": \"False\",\n    \"trueDescription\": \"serve true\",\n    \"falseDescription\": \"serve false\",\n    \"onVariation\": 0,\n    \"offVariation\": 1\n  },\n  \"defaultClientSideAvailability\": {\n    \"usingMobileKey\": true,\n    \"usingEnvironmentId\": true\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://app.launchdarkly.com/api/v2/projects/{projectKey}/flag-defaults")

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  \"tags\": [\n    \"tag-1\",\n    \"tag-2\"\n  ],\n  \"temporary\": true,\n  \"booleanDefaults\": {\n    \"trueDisplayName\": \"True\",\n    \"falseDisplayName\": \"False\",\n    \"trueDescription\": \"serve true\",\n    \"falseDescription\": \"serve false\",\n    \"onVariation\": 0,\n    \"offVariation\": 1\n  },\n  \"defaultClientSideAvailability\": {\n    \"usingMobileKey\": true,\n    \"usingEnvironmentId\": true\n  }\n}"

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

{
  "tags": [
    "tag-1",
    "tag-2"
  ],
  "temporary": true,
  "booleanDefaults": {
    "trueDisplayName": "True",
    "falseDisplayName": "False",
    "trueDescription": "serve true",
    "falseDescription": "serve false",
    "onVariation": 0,
    "offVariation": 1
  },
  "defaultClientSideAvailability": {
    "usingMobileKey": true,
    "usingEnvironmentId": true
  },
  "_links": {}
}

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

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

{
  "code": "forbidden",
  "message": "Forbidden. Access to the requested resource was denied."
}

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

{
  "code": "optimistic_locking_error",
  "message": "Conflict. Optimistic lock error. Try again later."
}

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