curl --request PATCH \
  --url https://app.launchdarkly.com/api/v2/projects/{projectKey} \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '
[
  {
    "op": "add",
    "path": "/tags/0",
    "value": "another-tag"
  }
]
'

import requests

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

payload = [
    {
        "op": "add",
        "path": "/tags/0",
        "value": "another-tag"
    }
]
headers = {
    "Authorization": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'PATCH',
  headers: {Authorization: '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify([{op: 'add', path: '/tags/0', value: 'another-tag'}])
};

fetch('https://app.launchdarkly.com/api/v2/projects/{projectKey}', 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}",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "PATCH",
  CURLOPT_POSTFIELDS => json_encode([
    [
        'op' => 'add',
        'path' => '/tags/0',
        'value' => 'another-tag'
    ]
  ]),
  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}"

	payload := strings.NewReader("[\n  {\n    \"op\": \"add\",\n    \"path\": \"/tags/0\",\n    \"value\": \"another-tag\"\n  }\n]")

	req, _ := http.NewRequest("PATCH", 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.patch("https://app.launchdarkly.com/api/v2/projects/{projectKey}")
  .header("Authorization", "<api-key>")
  .header("Content-Type", "application/json")
  .body("[\n  {\n    \"op\": \"add\",\n    \"path\": \"/tags/0\",\n    \"value\": \"another-tag\"\n  }\n]")
  .asString();

require 'uri'
require 'net/http'

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

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

request = Net::HTTP::Patch.new(url)
request["Authorization"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "[\n  {\n    \"op\": \"add\",\n    \"path\": \"/tags/0\",\n    \"value\": \"another-tag\"\n  }\n]"

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

{
  "_links": {
    "environments": {
      "href": "/api/v2/projects/my-project/environments",
      "type": "application/json"
    },
    "self": {
      "href": "/api/v2/projects/my-project",
      "type": "application/json"
    }
  },
  "_id": "57be1db38b75bf0772d11383",
  "key": "project-key-123abc",
  "includeInSnippetByDefault": true,
  "name": "My Project",
  "tags": [
    "ops"
  ],
  "environments": [
    {
      "_links": {
        "self": {
          "href": "/api/v2/projects/my-project/environments/my-environment",
          "type": "application/json"
        }
      },
      "_id": "57be1db38b75bf0772d11384",
      "key": "environment-key-123abc",
      "name": "My Environment",
      "apiKey": "sdk-xxx",
      "mobileKey": "mob-xxx",
      "color": "F5A623",
      "defaultTtl": 5,
      "secureMode": true,
      "defaultTrackEvents": false,
      "requireComments": true,
      "confirmChanges": true,
      "tags": [
        "ops"
      ],
      "critical": true,
      "_access": {
        "denied": [
          {
            "action": "<string>",
            "reason": {
              "effect": "allow",
              "resources": [
                "proj/*:env/*;qa_*:/flag/*"
              ],
              "notResources": [
                "<string>"
              ],
              "actions": [
                "*"
              ],
              "notActions": [
                "<string>"
              ],
              "role_name": "<string>"
            }
          }
        ],
        "allowed": [
          {
            "action": "<string>",
            "reason": {
              "effect": "allow",
              "resources": [
                "proj/*:env/*;qa_*:/flag/*"
              ],
              "notResources": [
                "<string>"
              ],
              "actions": [
                "*"
              ],
              "notActions": [
                "<string>"
              ],
              "role_name": "<string>"
            }
          }
        ]
      },
      "approvalSettings": {
        "required": true,
        "bypassApprovalsForPendingChanges": false,
        "minNumApprovals": 1,
        "canReviewOwnRequest": false,
        "canApplyDeclinedChanges": true,
        "serviceKind": "launchdarkly",
        "serviceConfig": {},
        "requiredApprovalTags": [
          "require-approval"
        ],
        "autoApplyApprovedChanges": true,
        "serviceKindConfigurationId": "1ef45a85-218f-4428-a8b2-a97e5f56c258"
      },
      "resourceApprovalSettings": {}
    }
  ],
  "defaultClientSideAvailability": {
    "usingMobileKey": true,
    "usingEnvironmentId": true
  },
  "_access": {
    "denied": [
      {
        "action": "<string>",
        "reason": {
          "effect": "allow",
          "resources": [
            "proj/*:env/*;qa_*:/flag/*"
          ],
          "notResources": [
            "<string>"
          ],
          "actions": [
            "*"
          ],
          "notActions": [
            "<string>"
          ],
          "role_name": "<string>"
        }
      }
    ],
    "allowed": [
      {
        "action": "<string>",
        "reason": {
          "effect": "allow",
          "resources": [
            "proj/*:env/*;qa_*:/flag/*"
          ],
          "notResources": [
            "<string>"
          ],
          "actions": [
            "*"
          ],
          "notActions": [
            "<string>"
          ],
          "role_name": "<string>"
        }
      }
    ]
  },
  "defaultReleasePipelineKey": "<string>"
}

{
  "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."
}