Text generation

Console

To use the Vertex AI Studio to send a chat prompt in the Google Cloud console, do the following:

1. In the Vertex AI section of the Google Cloud console, go to the Vertex AI Studio page.

   Go to Vertex AI Studio

2. In Start a conversation, click Text chat.

3. Optional: Configure the model and parameters:

   • Model: Select Gemini Pro.
   • Region: Select the region that you want to use.

   • Temperature: Use the slider or textbox to enter a value for temperature.

     The temperature is used for sampling during response generation, which occurs when topP and topK are applied. Temperature controls the degree of randomness in token selection. Lower temperatures are good for prompts that require a less open-ended or creative response, while higher temperatures can lead to more diverse or creative results. A temperature of 0 means that the highest probability tokens are always selected. In this case, responses for a given prompt are mostly deterministic, but a small amount of variation is still possible.

     If the model returns a response that's too generic, too short, or the model gives a fallback response, try increasing the temperature.

   • Output token limit: Use the slider or textbox to enter a value for the max output limit.

     Maximum number of tokens that can be generated in the response. A token is approximately four characters. 100 tokens correspond to roughly 60-80 words.

     Specify a lower value for shorter responses and a higher value for potentially longer responses.

   • Add stop sequence: Optional. Enter a stop sequence, which is a series of characters that includes spaces. If the model encounters a stop sequence, the response generation stops. The stop sequence isn't included in the response, and you can add up to five stop sequences.
4. Optional: To configure advanced parameters, click Advanced and configure as follows:

   Click to expand advanced configurations

   • Top-K: Use the slider or textbox to enter a value for top-K.

     Top-K changes how the model selects tokens for output. A top-K of 1 means the next selected token is the most probable among all tokens in the model's vocabulary (also called greedy decoding), while a top-K of 3 means that the next token is selected from among the three most probable tokens by using temperature.

     For each token selection step, the top-K tokens with the highest probabilities are sampled. Then tokens are further filtered based on top-P with the final token selected using temperature sampling.

     Specify a lower value for less random responses and a higher value for more random responses.

   • Top-P: Use the slider or textbox to enter a value for top-P. Tokens are selected from most probable to the least until the sum of their probabilities equals the value of top-P. For the least variable results, set top-P to 0.
   • Enable Grounding: Add a grounding source and path to customize this feature.
5. Enter your text prompt in the Prompt pane. The model uses previous messages as context for new responses.
6. Optional: To display the number of text tokens, click View tokens. You can view the tokens or token IDs of your text prompt.
   • To view the tokens in the text prompt that are highlighted with different colors marking the boundary of each token ID, click Token ID to text. Media tokens aren't supported.
   • To view the token IDs, click Token ID.

     To close the tokenizer tool pane, click X, or click outside of the pane.

7. Click Submit.
8. Optional: To save your prompt to My prompts, click save_alt Save.
9. Optional: To get the Python code or a curl command for your prompt, click code Get code.
10. Optional: To clear all previous messages, click delete Clear conversation

REST

Before using any of the request data, make the following replacements:

• GENERATE_RESPONSE_METHOD: The type of response that you want the model to generate. Choose a method that generates how you want the model's response to be returned:
  • streamGenerateContent: The response is streamed as it's being generated to reduce the perception of latency to a human audience.
  • generateContent: The response is returned after it's fully generated.
• LOCATION: The region to process the request. Available options include the following:

  Click to expand a partial list of available regions

  • us-central1
  • us-west4
  • northamerica-northeast1
  • us-east4
  • us-west1
  • asia-northeast3
  • asia-southeast1
  • asia-northeast1
• PROJECT_ID: Your project ID.
• MODEL_ID: The model ID of the multimodal model that you want to use.
• TEXT1

  The text instructions to include in the first prompt of the multi-turn conversation. For example, What are all the colors in a rainbow?
• TEXT2

  The text instructions to include in the second prompt. For example, Why does it appear when it rains?
• TEMPERATURE: The temperature is used for sampling during response generation, which occurs when topP and topK are applied. Temperature controls the degree of randomness in token selection. Lower temperatures are good for prompts that require a less open-ended or creative response, while higher temperatures can lead to more diverse or creative results. A temperature of 0 means that the highest probability tokens are always selected. In this case, responses for a given prompt are mostly deterministic, but a small amount of variation is still possible.

  If the model returns a response that's too generic, too short, or the model gives a fallback response, try increasing the temperature.

To send your request, choose one of these options:

cat > request.json << 'EOF'
{
  "contents": [
    {
      "role": "user",
      "parts": { "text": "TEXT1" }
    },
    {
      "role": "model",
      "parts": { "text": "What a great question!" }
    },
    {
      "role": "user",
      "parts": { "text": "TEXT2" }
    }
  ],
  "generation_config": {
    "temperature": TEMPERATURE
  }
}
EOF

curl -X POST \
     -H "Authorization: Bearer $(gcloud auth print-access-token)" \
     -H "Content-Type: application/json; charset=utf-8" \
     -d @request.json \
     "https://LOCATION-aiplatform.googleapis.com/v1/projects/PROJECT_ID/locations/LOCATION/publishers/google/models/MODEL_ID:GENERATE_RESPONSE_METHOD"

@'
{
  "contents": [
    {
      "role": "user",
      "parts": { "text": "TEXT1" }
    },
    {
      "role": "model",
      "parts": { "text": "What a great question!" }
    },
    {
      "role": "user",
      "parts": { "text": "TEXT2" }
    }
  ],
  "generation_config": {
    "temperature": TEMPERATURE
  }
}
'@  | Out-File -FilePath request.json -Encoding utf8

$cred = gcloud auth print-access-token
$headers = @{ "Authorization" = "Bearer $cred" }

Invoke-WebRequest `
    -Method POST `
    -Headers $headers `
    -ContentType: "application/json; charset=utf-8" `
    -InFile request.json `
    -Uri "https://LOCATION-aiplatform.googleapis.com/v1/projects/PROJECT_ID/locations/LOCATION/publishers/google/models/MODEL_ID:GENERATE_RESPONSE_METHOD" | Select-Object -Expand Content

You should receive a JSON response similar to the following.

{
  "candidates": [
    {
      "content": {
        "role": "model",
        "parts": [
          {
            "text": "You're right to ask that! Rainbows are a beautiful and fascinating phenomenon. Here's the breakdown:\n\n**1. Sunlight and Water Droplets:**\n\n* Rainbows are created when sunlight interacts with water droplets suspended in the air, typically after rain.\n\n**2. Refraction and Reflection:**\n\n* **Refraction:** When sunlight enters a water droplet, it bends or refracts. This bending is different for each color of light (red bends the least, violet the most).\n* **Reflection:** Inside the droplet, the light bounces off the back surface and then refracts again as it exits the droplet.\n\n**3. Dispersion:**\n\n* The refraction and reflection process separates the white sunlight into its component colors, just like a prism. This separation of colors is called dispersion.\n\n**4. Our Perspective:**\n\n* You only see a rainbow when you're standing with the sun behind you and the rain in front of you. The colors appear in an arc because the angle at which the light refracts and reflects is specific for each color.\n\n**In short:**\n\nRainbows are created when sunlight hits water droplets in the air, causing the light to be refracted, reflected, and dispersed into its individual colors.  \n"
          }
        ]
      },
      "finishReason": "STOP",
      "safetyRatings": [
        {
          "category": "HARM_CATEGORY_HATE_SPEECH",
          "probability": "NEGLIGIBLE",
          "probabilityScore": 0.06255973,
          "severity": "HARM_SEVERITY_NEGLIGIBLE",
          "severityScore": 0.039937314
        },
        {
          "category": "HARM_CATEGORY_DANGEROUS_CONTENT",
          "probability": "NEGLIGIBLE",
          "probabilityScore": 0.096705794,
          "severity": "HARM_SEVERITY_NEGLIGIBLE",
          "severityScore": 0.08404062
        },
        {
          "category": "HARM_CATEGORY_HARASSMENT",
          "probability": "NEGLIGIBLE",
          "probabilityScore": 0.10818896,
          "severity": "HARM_SEVERITY_NEGLIGIBLE",
          "severityScore": 0.036631368
        },
        {
          "category": "HARM_CATEGORY_SEXUALLY_EXPLICIT",
          "probability": "NEGLIGIBLE",
          "probabilityScore": 0.116764,
          "severity": "HARM_SEVERITY_NEGLIGIBLE",
          "severityScore": 0.05023736
        }
      ]
    }
  ],
  "usageMetadata": {
    "promptTokenCount": 22,
    "candidatesTokenCount": 256,
    "totalTokenCount": 278
  }
}

SDKs

You can use the Google Gen AI SDK to send requests if you're using Gemini 2.0 Flash.

The following sample shows a non-streaming text generation request.

pip install --upgrade google-genai

# Replace the `GOOGLE_CLOUD_PROJECT` and `GOOGLE_CLOUD_LOCATION` values
# with appropriate values for your project.
export GOOGLE_CLOUD_PROJECT=GOOGLE_CLOUD_PROJECT
export GOOGLE_CLOUD_LOCATION=global
export GOOGLE_GENAI_USE_VERTEXAI=True

from google import genai
from google.genai.types import HttpOptions

client = genai.Client(http_options=HttpOptions(api_version="v1"))
response = client.models.generate_content(
    model="gemini-2.5-flash",
    contents="How does AI work?",
)
print(response.text)
# Example response:
# Okay, let's break down how AI works. It's a broad field, so I'll focus on the ...
#
# Here's a simplified overview:
# ...

# Replace the `GOOGLE_CLOUD_PROJECT` and `GOOGLE_CLOUD_LOCATION` values
# with appropriate values for your project.
export GOOGLE_CLOUD_PROJECT=GOOGLE_CLOUD_PROJECT
export GOOGLE_CLOUD_LOCATION=global
export GOOGLE_GENAI_USE_VERTEXAI=True

import (
	"context"
	"fmt"
	"io"

	"google.golang.org/genai"
)

// generateWithText shows how to generate text using a text prompt.
func generateWithText(w io.Writer) error {
	ctx := context.Background()

	client, err := genai.NewClient(ctx, &genai.ClientConfig{
		HTTPOptions: genai.HTTPOptions{APIVersion: "v1"},
	})
	if err != nil {
		return fmt.Errorf("failed to create genai client: %w", err)
	}

	resp, err := client.Models.GenerateContent(ctx,
		"gemini-2.5-flash",
		genai.Text("How does AI work?"),
		nil,
	)
	if err != nil {
		return fmt.Errorf("failed to generate content: %w", err)
	}

	respText := resp.Text()

	fmt.Fprintln(w, respText)
	// Example response:
	// That's a great question! Understanding how AI works can feel like ...
	// ...
	// **1. The Foundation: Data and Algorithms**
	// ...

	return nil
}

npm install @google/genai

# Replace the `GOOGLE_CLOUD_PROJECT` and `GOOGLE_CLOUD_LOCATION` values
# with appropriate values for your project.
export GOOGLE_CLOUD_PROJECT=GOOGLE_CLOUD_PROJECT
export GOOGLE_CLOUD_LOCATION=global
export GOOGLE_GENAI_USE_VERTEXAI=True

const {GoogleGenAI} = require('@google/genai');

const GOOGLE_CLOUD_PROJECT = process.env.GOOGLE_CLOUD_PROJECT;
const GOOGLE_CLOUD_LOCATION = process.env.GOOGLE_CLOUD_LOCATION || 'global';

async function generateContent(
  projectId = GOOGLE_CLOUD_PROJECT,
  location = GOOGLE_CLOUD_LOCATION
) {
  const ai = new GoogleGenAI({
    vertexai: true,
    project: projectId,
    location: location,
  });

  const response = await ai.models.generateContent({
    model: 'gemini-2.5-flash',
    contents: 'How does AI work?',
  });

  console.log(response.text);

  return response.text;
}

# Replace the `GOOGLE_CLOUD_PROJECT` and `GOOGLE_CLOUD_LOCATION` values
# with appropriate values for your project.
export GOOGLE_CLOUD_PROJECT=GOOGLE_CLOUD_PROJECT
export GOOGLE_CLOUD_LOCATION=global
export GOOGLE_GENAI_USE_VERTEXAI=True

import com.google.genai.Client;
import com.google.genai.types.Content;
import com.google.genai.types.GenerateContentResponse;
import com.google.genai.types.HttpOptions;
import com.google.genai.types.Part;

public class TextGenerationWithText {

  public static void main(String[] args) {
    // TODO(developer): Replace these variables before running the sample.
    String modelId = "gemini-2.5-flash";
    generateContent(modelId);
  }

  // Generates text with text input
  public static String generateContent(String modelId) {
    // Initialize client that will be used to send requests. This client only needs to be created
    // once, and can be reused for multiple requests.
    try (Client client =
        Client.builder()
            .location("global")
            .vertexAI(true)
            .httpOptions(HttpOptions.builder().apiVersion("v1").build())
            .build()) {

      GenerateContentResponse response =
          client.models.generateContent(modelId, "How does AI work?", null);

      System.out.print(response.text());
      // Example response:
      // Okay, let's break down how AI works. It's a broad field, so I'll focus on the ...
      //
      // Here's a simplified overview:
      // ...
      return response.text();
    }
  }
}