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How to Use Google Gemini: Web, Mobile, and API Guide

Start a Gemini chat on the web or your phone, try practical prompts, and follow a separate production API example.

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For a quick chat, go to gemini.google.com, enter a prompt, and select Submit. You can also use the Gemini app on Android, iPhone, or iPad. If you’re building software, use the Gemini API—a separate developer route—not the consumer chat app.

Start a chat on the web

  1. Open gemini.google.com in a supported browser.
  2. Type a question or instruction in the prompt box.
  3. Select Submit. On a computer, you can also select Add files to include a supported file or image.
  4. Ask a follow-up to continue, or choose New chat to start a separate conversation. (Google’s computer instructions; file-upload instructions)

Some Gemini web features are available without signing in. Sign in with a Google Account for additional features or to save Gemini Apps activity. Work or school accounts may need Gemini Apps access. (Google’s sign-in requirements)

Use Gemini on your phone

Android app

If you don’t have the app, download Gemini from Google Play. Sign in with a Google Account to use the Android app; work or school accounts need Gemini Apps access. (Android setup requirements)

Open the app, enter your question or prompt in the text box at the bottom, then tap Submit. To attach a supported photo or file, tap Add files and follow the on-screen instructions. (Google’s Android app instructions)

To use Gemini as your mobile assistant, the Google app must be set as your device’s default assist app. Setup and activation options can vary by device. (Android app setup)

iPhone or iPad app

If you don’t have the app, download Google Gemini from the App Store. Open it, then tap Keyboard to enter a prompt, Microphone to speak, or Live to start a real-time voice conversation. For voice input, Google’s instructions say to tap Send to share your prompt. Some features work without signing in; additional features and saving Gemini Apps activity require a Google Account. Availability can depend on your device, language, account, or location. (Google’s iPhone and iPad instructions)

Try Gemini with a practical prompt

These are examples to adapt—not tested outcomes or guaranteed results:

  • Draft: “Write a friendly, concise email asking to reschedule a meeting. Leave the new date as a placeholder.”
  • Revise: “Make this paragraph clearer and shorter while keeping its meaning, names, and dates unchanged: [paste text].”
  • Brainstorm: “Suggest five low-cost lunch ideas for a team of eight. Include estimated prep time.”
  • Ask about a file: Attach a document, then ask, “Summarize the main decisions and deadlines. If a detail isn’t in the document, say so.” File and image options depend on the app, account, and feature available to you.

You can refine a response by specifying the audience, format, constraints, or how it should handle missing information. That’s practical prompting advice, not a special setting or a guarantee of accuracy.

Check important answers before acting on them. Google warns that Gemini can make mistakes and recommends double-checking responses. (Google’s file and image guidance)

Consumer Gemini or developer API?

Use the web or mobile app when you want to chat directly. Use the Gemini API when your application needs to send model requests programmatically. Google recommends the Interactions API for new projects; the generateContent API remains supported. (Interactions API documentation)

Make a Gemini API request for a production integration

This example uses Google’s Gemini 4 Argon model ID, gemini-4-argon, with the Interactions API. Confirm model access, billing, and project limits before deploying. (Model guide and example)

1. Create or select a project and API key

Create or view a Gemini API key in Google AI Studio. Google says new users receive a default Google Cloud project and API key after accepting the Terms of Service. If you already have a Google Cloud project, import it into AI Studio before creating a key for that project. (Google’s API-key instructions)

Store the key outside your source code. Google warns not to expose API keys in client-side web or mobile code; keep production credentials on a server. For local development, set the key as an environment variable:

export GEMINI_API_KEY="YOUR_API_KEY"

2. Activate paid access for Gemini 4 Argon

Gemini 4 Argon is not available on the Gemini API Free tier. Before sending the example request, open AI Studio’s API keys or Projects page, choose the project, and select Set up billing. Google’s billing guide says paid-tier setup requires linking a billing account and prepaying at least $5 (or the equivalent in another currency). (Official pricing; billing setup)

3. Install the Python SDK and send a request

Install Google’s GenAI Python SDK, then run the documented Interactions API pattern. The client reads the key from the environment variable above. (SDK installation; model quickstart)

pip install -U google-genai
from google import genai

client = genai.Client()
interaction = client.interactions.create(
    model="gemini-4-argon",
    input="Give me three concise names for a neighborhood coffee shop.",
)
print(interaction.output_text)

interaction.output_text is the SDK helper for reading the generated text. This is a documentation-based example, not a report of a request tested for this article.

4. Check pricing and project limits before deployment

As of November 8, 2026, Google lists introductory Gemini 4 Argon API rates through November 30, 2026 of USD $2 per 1 million input tokens and USD $10 per 1 million output tokens. The listed rates afterward are USD $4 and USD $20 per 1 million tokens, respectively. These are API usage rates, not a consumer subscription price. Check the official pricing page before deploying because rates can change.

Check the selected project’s active limits in the Gemini API rate-limits guide, which links to the active-limits view in AI Studio. Limits are project- and model-dependent; the documented dimensions include requests per minute (RPM), input tokens per minute (TPM), and requests per day (RPD). (Google’s rate-limit documentation)

Quick checklist

  • Just want to chat? Open gemini.google.com or install the Gemini app, then submit a prompt.
  • Using Android? Install the app from Google Play and sign in with a Google Account.
  • Using iPhone or iPad? Install the app from the App Store; sign-in needs depend on the feature.
  • Need to include a file or image? Use Add files where it’s available.
  • Building an application? Use the Gemini API, keep credentials server-side, activate the required billing tier, and check model access and project limits.
  • Relying on an answer? Verify important details against a trusted source.

Sources

Use Gemini Apps - Computer - Gemini Apps Help

Upload & analyze files in Gemini Apps - Computer

Upload & analyze files in Gemini Apps - Android phone & tablet

Get started with the Gemini mobile app - Android

Get started with the Gemini mobile app - iPhone and iPad

What you need to sign in to Gemini Apps

Google Gemini - Google Play

Google Gemini - App Store

Interactions API - Gemini API

What's new in Gemini 4 Argon - Interactions API

Using Gemini API keys

Billing - Gemini API

Gemini Developer API pricing

Rate limits - Gemini API

Get started with the Gemini API

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