curl --request PUT \
  --url https://{tenant}/api/apis/{apiId} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "api_definition": {
    "api_id": "b84fe1a04e5648927971c0557971565c",
    "auth": {
      "auth_header_name": "authorization"
    },
    "definition": {
      "key": "version",
      "location": "header"
    },
    "name": "Update API name",
    "org_id": "664a14650619d40001f1f00f",
    "proxy": {
      "listen_path": "/updated-tyk-api-test/",
      "strip_listen_path": true,
      "target_url": "https://httpbin.org"
    },
    "use_oauth2": true,
    "version_data": {
      "not_versioned": true,
      "versions": {
        "Default": {
          "name": "Default"
        }
      }
    }
  }
}
'

import requests

url = "https://{tenant}/api/apis/{apiId}"

payload = { "api_definition": {
        "api_id": "b84fe1a04e5648927971c0557971565c",
        "auth": { "auth_header_name": "authorization" },
        "definition": {
            "key": "version",
            "location": "header"
        },
        "name": "Update API name",
        "org_id": "664a14650619d40001f1f00f",
        "proxy": {
            "listen_path": "/updated-tyk-api-test/",
            "strip_listen_path": True,
            "target_url": "https://httpbin.org"
        },
        "use_oauth2": True,
        "version_data": {
            "not_versioned": True,
            "versions": { "Default": { "name": "Default" } }
        }
    } }
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'PUT',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    api_definition: {
      api_id: 'b84fe1a04e5648927971c0557971565c',
      auth: {auth_header_name: 'authorization'},
      definition: {key: 'version', location: 'header'},
      name: 'Update API name',
      org_id: '664a14650619d40001f1f00f',
      proxy: {
        listen_path: '/updated-tyk-api-test/',
        strip_listen_path: true,
        target_url: 'https://httpbin.org'
      },
      use_oauth2: true,
      version_data: {not_versioned: true, versions: {Default: {name: 'Default'}}}
    }
  })
};

fetch('https://{tenant}/api/apis/{apiId}', 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://{tenant}/api/apis/{apiId}",
  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([
    'api_definition' => [
        'api_id' => 'b84fe1a04e5648927971c0557971565c',
        'auth' => [
                'auth_header_name' => 'authorization'
        ],
        'definition' => [
                'key' => 'version',
                'location' => 'header'
        ],
        'name' => 'Update API name',
        'org_id' => '664a14650619d40001f1f00f',
        'proxy' => [
                'listen_path' => '/updated-tyk-api-test/',
                'strip_listen_path' => true,
                'target_url' => 'https://httpbin.org'
        ],
        'use_oauth2' => true,
        'version_data' => [
                'not_versioned' => true,
                'versions' => [
                                'Default' => [
                                                                'name' => 'Default'
                                ]
                ]
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "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://{tenant}/api/apis/{apiId}"

	payload := strings.NewReader("{\n  \"api_definition\": {\n    \"api_id\": \"b84fe1a04e5648927971c0557971565c\",\n    \"auth\": {\n      \"auth_header_name\": \"authorization\"\n    },\n    \"definition\": {\n      \"key\": \"version\",\n      \"location\": \"header\"\n    },\n    \"name\": \"Update API name\",\n    \"org_id\": \"664a14650619d40001f1f00f\",\n    \"proxy\": {\n      \"listen_path\": \"/updated-tyk-api-test/\",\n      \"strip_listen_path\": true,\n      \"target_url\": \"https://httpbin.org\"\n    },\n    \"use_oauth2\": true,\n    \"version_data\": {\n      \"not_versioned\": true,\n      \"versions\": {\n        \"Default\": {\n          \"name\": \"Default\"\n        }\n      }\n    }\n  }\n}")

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

	req.Header.Add("Authorization", "Bearer <token>")
	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://{tenant}/api/apis/{apiId}")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"api_definition\": {\n    \"api_id\": \"b84fe1a04e5648927971c0557971565c\",\n    \"auth\": {\n      \"auth_header_name\": \"authorization\"\n    },\n    \"definition\": {\n      \"key\": \"version\",\n      \"location\": \"header\"\n    },\n    \"name\": \"Update API name\",\n    \"org_id\": \"664a14650619d40001f1f00f\",\n    \"proxy\": {\n      \"listen_path\": \"/updated-tyk-api-test/\",\n      \"strip_listen_path\": true,\n      \"target_url\": \"https://httpbin.org\"\n    },\n    \"use_oauth2\": true,\n    \"version_data\": {\n      \"not_versioned\": true,\n      \"versions\": {\n        \"Default\": {\n          \"name\": \"Default\"\n        }\n      }\n    }\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://{tenant}/api/apis/{apiId}")

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

request = Net::HTTP::Put.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"api_definition\": {\n    \"api_id\": \"b84fe1a04e5648927971c0557971565c\",\n    \"auth\": {\n      \"auth_header_name\": \"authorization\"\n    },\n    \"definition\": {\n      \"key\": \"version\",\n      \"location\": \"header\"\n    },\n    \"name\": \"Update API name\",\n    \"org_id\": \"664a14650619d40001f1f00f\",\n    \"proxy\": {\n      \"listen_path\": \"/updated-tyk-api-test/\",\n      \"strip_listen_path\": true,\n      \"target_url\": \"https://httpbin.org\"\n    },\n    \"use_oauth2\": true,\n    \"version_data\": {\n      \"not_versioned\": true,\n      \"versions\": {\n        \"Default\": {\n          \"name\": \"Default\"\n        }\n      }\n    }\n  }\n}"

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

{
  "Message": "API updated",
  "Meta": null,
  "Status": "OK"
}

{
  "Message": "Invalid `ID` value",
  "Meta": null,
  "Status": "Error"
}

{
  "Message": "Not authorised",
  "Meta": null,
  "Status": "Error"
}

{
  "Message": "access denied: You do not have permission to access  /api/apis/{apiId}",
  "Meta": null,
  "Status": "Error"
}

{
  "Message": "API definition does not exist",
  "Meta": null,
  "Status": "Error"
}

{
  "Message": "Error while validating schema",
  "Meta": null,
  "Status": "Error"
}