PHP Client Library for Dialogflow v2 API: Getting started

If you have the choice to go for Python or NodeJS instead of PHP, I recommend using the other two options (between the two, I prefer Python). You will probably find it quite hard to find a lot of discussion online about using PHP with Dialogflow.  

This is a very basic tutorial for getting started with the PHP Client Library for Dialogflow API v2. I don’t cover any advanced stuff, but it should help you get started.

1 Create a new folder for your project

In my case, I am just calling it quickstart.

2 Download the client secret JSON file for your v2 Dialogflow agent into the quickstart folder

2.1 Make sure v2 API is enabled

2.2 Click on the service account email address

You will be taken to the Google Cloud Console.

2.3 Click on the Create Service Account link at the top of the console menu

2.4 Provide a suitable name for the service account

2.5 Select Project -> Owner in the Role dropdown box

2.6 Make sure you check the Furnish a new private key box. Keep the key type as JSON

2.7 Click on the create link

2.8 You will be prompted to save the client secret JSON file. Save the file as client-secret.json to the quickstart folder you just created

New User Interface

Update: After creating this tutorial, I realized that you can do everything here using the Dialogflow API Admin role. The UI has changed a bit now, but essentially you will create a new service account, and choose the role Dialogflow -> API Admin and you will be able to proceed with the rest of the steps in the tutorial. If you are interested in understanding what these roles are, you might want to check out my REST API v2 course.

2.1 Click on Create Service Account

2.2 Select Dialogflow API Admin as the role for the service account

Click on + Create Key button, and select JSON and click on the CREATE button from the slide out. Save the JSON file to the folder.

3 Install composer

If you have Homebrew on Mac, you can simply use

brew install composer

Otherwise you can look online for instructions on how to install composer.

4 Use composer to install Dialogflow client libraries

Before you can use this command, you need to make sure composer was correctly installed. You can use the command

composer require google/cloud-dialogflow

as specified here.

5 PHP Code

5.1 Create an example.php file in the quickstart directory. Your folder structure should look like this at this point. The vendor directory is created when you used composer to install the Dialogflow client libraries.

5.2 Add the required namespaces in example.php

namespace Google\Cloud\Samples\Dialogflow;
use Google\Cloud\Dialogflow\V2\SessionsClient;
use Google\Cloud\Dialogflow\V2\TextInput;
use Google\Cloud\Dialogflow\V2\QueryInput;

5.2 Use Composer’s autoload to add the classes from the vendor directory

require __DIR__.'/vendor/autoload.php';

5.3 Add the following function to example.php

function detect_intent_texts($projectId, $text, $sessionId, $languageCode = 'en-US')
    // new session
    $test = array('credentials' => 'client-secret.json');
    $sessionsClient = new SessionsClient($test);
    $session = $sessionsClient->sessionName($projectId, $sessionId ?: uniqid());
    printf('Session path: %s' . PHP_EOL, $session);

    // create text input
    $textInput = new TextInput();

    // create query input
    $queryInput = new QueryInput();

    // get response and relevant info
    $response = $sessionsClient->detectIntent($session, $queryInput);
    $queryResult = $response->getQueryResult();
    $queryText = $queryResult->getQueryText();
    $intent = $queryResult->getIntent();
    $displayName = $intent->getDisplayName();
    $confidence = $queryResult->getIntentDetectionConfidence();
    $fulfilmentText = $queryResult->getFulfillmentText();

    // output relevant info
    print(str_repeat("=", 20) . PHP_EOL);
    printf('Query text: %s' . PHP_EOL, $queryText);
    printf('Detected intent: %s (confidence: %f)' . PHP_EOL, $displayName,
    printf('Fulfilment text: %s' . PHP_EOL, $fulfilmentText);


5.4 Call the function with the following parameters


Replace your-project-id with your Dialogflow project ID. The third parameter, sessionID, can be any string for this purpose. However, if you are going to be using the client library to manage an entire conversation, your sessionID must be the same across an entire conversation session.

6 Run the code

Now in your Terminal type

php example.php

and you should see the following output. (Make sure you have an actual WelcomeIntent in your Dialogflow agent which has “hi” as one of its training phrases).


Leave your feedback in the comments section below.

About this website

BotFlo1 was created by Aravind Mohanoor as a website which provided training and tools for non-programmers who were2 building Dialogflow chatbots.

This website has now expanded into other topics in Natural Language Processing, including the recent Large Language Models (GPT etc.) with a special focus on helping non-programmers identify and use the right tool for their specific NLP task.

1 BotFlo was previously called MiningBusinessData. That is why you see that name in many videos

2 And still are building Dialogflow chatbots. Dialogflow ES first evolved into Dialogflow CX, and Dialogflow CX itself evolved to add Generative AI features in mid-2023

  • [17-May-2023 11:58:10 UTC] PHP Fatal error: Uncaught GoogleApiCoreApiException: {
    “message”: “com.google.apps.framework.request.NotFoundException: No DesignTimeAgent found for project ‘nies-387004’.”,
    “code”: 5,
    “status”: “NOT_FOUND”,
    “details”: []

    thrown in /home/nabcbtest/public_html/public/workflow/vendor/google/gax/src/ApiException.php on line 267

  • Hello,

    I’ve been following this tutorial step-by-step, however my code get stuck when calling “detectIntent” method.

    Here’s the code :
    $response = $sessionsClient->detectIntent($session, $queryInput);

    At this point, my code doesn’t return anything. It also doesn’t return any Exception.

    Could you help me, please?

  • Me tira este error, que puede ser??

    Session path: projects/********/agent/sessions/123456

    Fatal error: Uncaught GoogleApiCoreApiException: {
    “message”: “IAM permission ‘dialogflow.sessions.detectIntent’ on ‘projects/*********/agent’ denied.”,
    “code”: 7,
    “status”: “PERMISSION_DENIED”,
    “details”: []

    thrown in /Users/***********/Desktop/test/vendor/google/gax/src/ApiException.php on line 139

    • I am not sure, but the permission issue makes me wonder if you have saved the client-secret JSON file correctly in the same folder as your PHP file and also referenced it with the correct filename in your code.

      • Quick question, do you perhaps know how to set context with this? I have tried everything. I included the ” use GoogleCloudDialogflowV2Context;” in the code and then added the following, but it still fails. Please tell me you know how to do this?

        // $context is a normal php array containing the values
        $contextInput = new Context();

      • Nevermind, my friend. I figured it out. In case anyone else needs this. Here is what I did.

        I added these as well:

        use GoogleProtobufValue;
        use GoogleProtobufStruct;

        Then I created my context like this
        $contextInput = new Context();

        $contextValue = new Value();
        $context[‘parameters’][‘number_param_key’] = $contextValue->setNumberValue($context[“parameters”][“number_param”]); // In my case I was passing a number

        $contextStruct = new Struct();


        This seems to have worked and my agent is chatting again with the context set !

        Thanks anyway!

        • Hi Christopher,

          What are the exact contents of $context? Specifically when you call ‘$contextStruct->setFields($context[鈥榩arameters鈥橾);’ what is passed as $context[鈥榩arameters鈥橾?

          • Hey it’s me again and amidst this corona scare nobody from support helped out. And their docs are cryptic as shit. So I figured it out:
            // create query input
            $queryInput = new QueryInput();

            //$contextPath = $session . ‘/contexts/’ . ‘masters’;
            $contextPath = $session . ‘/contexts/’ . $contextText;
            $context = new Context();

            $queryParams = new QueryParameters([‘contexts’ => [$context]]);

            // get response and relevant info
            $response = $sessionsClient->detectIntent($session, $queryInput, [‘queryParams’ => $queryParams]);

  • Hello,

    How i can get a JSON response? 馃檪

    Like this:
    “responseId”: “ecffd044-d4b4-4613-978e-23b69dcc3110-f6406966”,
    “queryResult”: {
    “fulfillmentMessages”: [
    “platform”: “FACEBOOK”,
    “text”: {
    “text”: [
    “Hallo!nDit is een test werkt dit o”
    “message”: “text”
    “platform”: “FACEBOOK”,
    “quickReplies”: {
    “quickReplies”: [
    “title”: “Ja”
    “message”: “quickReplies”
    “platform”: “PLATFORM_UNSPECIFIED”,
    “text”: {
    “text”: [
    “Hallo!nDit is een test werkt dit o”
    “message”: “text”
    “outputContexts”: [],
    “queryText”: “Hello je meoder”,
    “speechRecognitionConfidence”: 0,
    “action”: “input.welcome”,
    “parameters”: {
    “fields”: {}
    “allRequiredParamsPresent”: true,
    “fulfillmentText”: “Hallo!nDit is een test werkt dit o”,
    “webhookSource”: “”,
    “webhookPayload”: null,
    “intent”: {
    “inputContextNames”: [],
    “events”: [],
    “trainingPhrases”: [],
    “outputContexts”: [],
    “parameters”: [],
    “messages”: [],
    “defaultResponsePlatforms”: [],
    “followupIntentInfo”: [],
    “name”: “projects/livebot-coftjp/agent/intents/70e47523-f9e3-402f-a1fc-20c496d5d846”,
    “displayName”: “Default Welcome Intent”,
    “priority”: 0,
    “isFallback”: false,
    “webhookState”: “WEBHOOK_STATE_UNSPECIFIED”,
    “action”: “”,
    “resetContexts”: false,
    “rootFollowupIntentName”: “”,
    “parentFollowupIntentName”: “”,
    “mlDisabled”: false
    “intentDetectionConfidence”: 0.3702174425125122,
    “diagnosticInfo”: null,
    “languageCode”: “nl”
    “webhookStatus”: null

  • Hi, Can I use this code to run on a server and call this example.php from chrome? I have checked this way but not working. I have also checked using putty. It also giving no output as well as no error. Any suggestions, please?

      • Yes, I am getting it on local machine. But now I think the server I have used is without SSL. Am I right that it will only work in “https” domain? But not any errors are listing!

        • To be honest, I am not entirely sure and it is quite hard to debug this. There are a couple of options: you can schedule a paid consultation if it is urgent. If not, give me a week or so, and I will create a tutorial which will use Heroku (and will be more easy to deploy to web).

  • Holes, espero q estes bien. Estoy explorando DialogFlow como soluci贸n, estoy consumiendo la API Rest con PHP, DialogFlow versi贸n free usando este tutorial muy 煤til.

    Tengo un s铆ntoma, consiste que solo tengo respuesta con la intensi贸n ‘Default Welcome Intent’, en una intensi贸n diferente me arroja un error. Ajunto pantallazo:

    En los 2 primeras peticiones va con frase de entrenamiento de intensi贸n ‘Default Welcome Intent’, el cual hay respuesta satisfactoria.
    En la 3 petici贸n, va con una frase de entrenamiento de una intensi贸n nueva, pero arroja un error.
    Nota: Las 3 peticiones contiene el mismo sessionId. Al final del email esta en detalle el error.


    [root@centos-s-1vcpu-1gb-sgp1-01 dialogflow]# php Calldiaglogflow.php
    Session path: projects/agente-virtual-acfff/agent/sessions/12345678
    Hola! Soy asistente virtual IngeTecno, Donde vives ?[root@centos-s-1vcpu-1gb-sgp1-01 dialogflow]#
    [root@centos-s-1vcpu-1gb-sgp1-01 dialogflow]#
    [root@centos-s-1vcpu-1gb-sgp1-01 dialogflow]# php Calldiaglogflow.php
    Session path: projects/agente-virtual-acfff/agent/sessions/12345678
    Hola! Soy asistente virtual IngeTecno, Donde vives ?[root@centos-s-1vcpu-1gb-sgp1-01 dialogflow]#
    [root@centos-s-1vcpu-1gb-sgp1-01 dialogflow]#
    [root@centos-s-1vcpu-1gb-sgp1-01 dialogflow]# php Calldiaglogflow.php
    Session path: projects/agente-virtual-acfff/agent/sessions/12345678
    PHP Fatal error: Uncaught Error: Call to undefined function GoogleProtobufInternalbccomp() in /var/lib/asterisk/agi-bin/dialogflow/vendor/google/protobuf/src/Google/Protobuf/Internal/Message.php:900
    Stack trace:
    #0 /var/lib/asterisk/agi-bin/dialogflow/vendor/google/protobuf/src/Google/Protobuf/Internal/Message.php(1218): GoogleProtobufInternalMessage->convertJsonValueToProtoValue(4, Object(GoogleProtobufInternalFieldDescriptor))
    #1 /var/lib/asterisk/agi-bin/dialogflow/vendor/google/protobuf/src/Google/Protobuf/Internal/Message.php(1167): GoogleProtobufInternalMessage->mergeFromArrayJsonImpl(Array)
    #2 /var/lib/asterisk/agi-bin/dialogflow/vendor/google/protobuf/src/Google/Protobuf/Internal/Message.php(815): GoogleProtobufInternalMessage->mergeFromJsonArray(Array)
    #3 /var/lib/asterisk/agi-bin/dialogflow/vendor/google/protobuf/src/Google/Protobuf/Internal/Message.php(1218): GoogleProtobufInternalMessage->convertJsonValueToProtoValue(Array, Object(GoogleProtobufInternalFieldDescriptor))
    #4 /var/lib/asterisk/ag in /var/lib/asterisk/agi-bin/dialogflow/vendor/google/protobuf/src/Google/Protobuf/Internal/Message.php on line 900

    • Its hard to say, but it looks like you have some error in the URL endpoint you are using. Maybe someone else will pitch in if they have run into the same issue.

      • i searchedit on google and cannot find any response or similiar

        by endpoint, what do you mean?

        this is the entire error.

        request.CRITICAL: Uncaught PHP Exception GoogleApiCoreValidationException: “Cannot bind segment ‘{project=*}’ to value ”” at /opt/sdp/gchat/www/chatgenerico/vendor/google/gax/src/ApiCore/ResourceTemplate/Segment.php line 121 {“exception”:”[object] (Google\ApiCore\ValidationException(code: 0): Cannot bind segment ‘{project=*}’ to value ” at /opt/sdp/gchat/www/chatgenerico/vendor/google/gax/src/ApiCore/ResourceTemplate/Segment.php:121)”} []

        • I meant that something might be wrong with the structure of the URL you are calling to access the API. I haven’t seen this error, so I am not sure what is causing it.

  • Been trying to get this working. Keep running into permission issues. I enabled the dialogflow v2 API, created the service account, added the owner role to it, downloaded the JSON key…and I keep getting this as a response:

    PHP Fatal error: Uncaught GoogleApiCoreApiException: {
    “message”: “IAM permission ‘dialogflow.sessions.detectIntent’ on ‘projects/dialogflow-XXXXXX/agent’ denied.”,
    “code”: 7,
    “status”: “PERMISSION_DENIED”,
    “details”: []

    • I just tried it now, and it still works as described in this tutorial. My suggestion would be to start the project in a completely new directory, reinstall the libraries using composer and try again (in case the libraries got messed up somehow). One more thing you might want to check is to see if the Dialogflow API is enabled for your project (login to Google Cloud Console -> APIs and services from left menu -> Dashboard).

  • I have created a test chatbot and enabled V2 API and then created the service account by following above steps.
    After that I have installed V2 client library using composer and added the client-secret.json file in folder directory.
    While trying to use : composer require __DIR__.’/vendor/autoload.php’;
    getting below error:

    Could not find a matching version of package __DIR__.’/vendor/autoload.php’
    . Check the package spelling, your version constraint and that the package
    is available in a stability which matches your minimum-stability (stable).

    Please help

    • To clarify, the line

      require __DIR__.鈥/vendor/autoload.php鈥;

      goes inside your PHP code, right after the namespace section. Other than that, I am not sure what is causing the error, you might have to ask on some other forum.

  • Can you help please, I am trying to get the data from:

    but I can’t.
    I tried:
    json_decode($queryResult->getFulfillmentMessages()->serializeToJsonString(), true);
    but show me a error, serializeToJsonString doesn’t exist.

    I really will apreciate it.

    • Hey Walter,
      This solution worked for me. The response that is received from the queryResult is a protobuf repeated field. The payload that is required to be extracted can be accessed by calling the first element of the repeated field and serializing it to JSON string then decoding it.

      json_decode($queryResult->getFulfillmentMessages()[0]->serializeToJsonString(), true);

      This will give the payload in array format using which you can perform your operations on it.