Generate content using Vertex AI Express Mode

This sample utilizes Vertex AI Express Mode to generate text content.

Explore further

For detailed documentation that includes this code sample, see the following:

Code sample

Go

Before trying this sample, follow the Go setup instructions in the Vertex AI quickstart using client libraries. For more information, see the Vertex AI Go API reference documentation.

To authenticate to Vertex AI, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 

import (
	"context"
	"fmt"
	"io"

	"google.golang.org/genai"
)

var newClient = genai.NewClient

// generateContent shows how to use Vertex AI Express mode with an API key.
func generateContentWithApiKey(w io.Writer) error {
	ctx := context.Background()

	// TODO(developer): Replace with your actual API key
	apiKey := "YOUR_API_KEY"

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

	modelName := "gemini-2.5-flash"
	resp, err := client.Models.GenerateContent(ctx, modelName,
		[]*genai.Content{
			{Parts: []*genai.Part{
				{Text: "Explain bubble sort to me."},
			}, Role: "user"},
		},
		nil,
	)
	if err != nil {
		return fmt.Errorf("failed to generate content: %w", err)
	}

	fmt.Fprintln(w, resp.Text())

	// Example response:
	// Bubble Sort is a simple sorting algorithm that repeatedly steps through the list

	return nil
}

Python

Before trying this sample, follow the Python setup instructions in the Vertex AI quickstart using client libraries. For more information, see the Vertex AI Python API reference documentation.

To authenticate to Vertex AI, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 

from google import genai

# TODO(developer): Update below line
API_KEY = "YOUR_API_KEY"

client = genai.Client(vertexai=True, api_key=API_KEY)

response = client.models.generate_content(
    model="gemini-2.5-flash",
    contents="Explain bubble sort to me.",
)

print(response.text)
# Example response:
# Bubble Sort is a simple sorting algorithm that repeatedly steps through the list

What's next

To search and filter code samples for other Google Cloud products, see the Google Cloud sample browser.