How to Build an AI App with Google Sheets and Gemini (No-Code)

You type a single paragraph of plain English into a box. Minutes later, you get a working, multi-module web application. And the entire database runs on a simple spreadsheet. Knowing how to build an AI app with Google Sheets gives you a technical edge.

Spreadsheets are no longer just grids for accounting. They run active backends. By connecting the Gemini API to Google Apps Script, you bypass traditional database hosting entirely. You get user authentication, relational data fields, computed math, and file uploads out of the box. All without writing backend code.

So, we are going to build a travel agency management system. I will show you exactly how the architecture works. You will learn how to configure the Google Apps Script deployment. I will give you the exact prompt that generates the whole platform.

The architecture: Turning spreadsheets into software

You can build a custom web application using free Google tools. Replace your PostgreSQL database and Node.js server completely.

The stack breaks down into 4 components:

• The Database: Google Sheets stores all text, numbers, and references. Each module gets a dedicated sheet.
• File Storage: Google Drive is your AWS S3 bucket. A user uploads a profile picture or a PDF document. The file routes straight to a public Drive folder.
• The Backend API: Google Apps Script runs the server logic. It catches JSON payloads from the web interface and writes them to specific rows.
• The Brain: The Gemini API reads your text prompt. It automatically designs the database schema, field types, and relational links.

This setup creates a CRUD (Create, Read, Update, Delete) application. Users log in, add new records, edit entries, and delete mistakes. If you look into how to build a web app with Cursor AI, you know database management eats up time. This method removes database management completely.

Google Sheets versus traditional no-code platforms

Cost and control dictate your choice. Dedicated platforms lock your data inside their databases. If they raise prices, you pay.

With Google Sheets, your data lives in your own Google account. You own the raw data file. You can export it as a CSV at any time.

Apps Script speed handles internal tools fine. Tracking inventory or managing 50 client bookings works well. High-traffic projects demand traditional setups. For 1,000s of public users, check out how to deploy vibe coded apps using Dokploy.

Step 1: Deploying the backend script

You need the base Google Sheet template that contains the custom App Builder menu. Copy the file to your Google Drive. Then, activate the backend code.

1. Click on the Extensions menu at the top of your spreadsheet.
2. Select Apps Script. This opens a new tab showing the backend project files.
3. You don’t need to read or edit any code here. Just look for the blue Deploy button in the top right corner.
4. Click New deployment.
5. Click the gear icon next to “Select type” and choose Web app.

Now pay attention to the access settings. Beginners make a critical error here.

Configuring execution permissions

You must set Execute as to “Me”. This tells Google to use your account permissions to read and write to the spreadsheet. If you set it to “User accessing the web app”, every user needs edit access to your raw spreadsheet file. That ruins your security.

Next, set Who has access to “Anyone”. This makes the web interface public. Invited users hit the login screen without facing a Google Workspace permission wall.

Click Deploy. Google displays a security warning for an unverified app. Click “Advanced” and then “Go to script (unsafe)”. You grant your own code permission to edit your own spreadsheet. Copy the resulting Web App URL. You need it later.

Understanding Apps Script quotas

Google enforces strict limits on Apps Script. You get 6 minutes of execution time per script run. You can make 20,000 URL fetches per day.

If your travel agency app suddenly goes viral, the script crashes. This architecture targets small teams and internal operations. Keep your daily usage under 1,000 read and write requests.

Step 2: Connecting the Gemini AI brain

Go back to your spreadsheet. Click the custom menu called AI App Builder.

Paste the Web App URL you just copied. Then, provide a Gemini API key. Go to Google AI Studio and generate a free key. This 39-character string allows the spreadsheet to send prompts to Google’s large language model.

After saving the key, configure the main Owner account. Enter your name, email, and a password. This creates the super-admin profile. You use this account to log into the generated web app, manage users, and configure the business logo.

Step 3: Writing the application prompt

Open the AI App Builder dialogue in the spreadsheet. Tell Gemini exactly what modules you want. Detail the data fields and how they connect.

Here is the exact prompt for a complete travel agency system:

Hit Generate. Gemini reads this text and translates it into a JSON schema. It identifies the distinct field types.

It sees “cover image” and creates an image upload handler. It sees “checkbox” and creates a boolean toggle. It reads the math instruction and bolts on a computed field formula.

Parsing the JSON payload

Gemini returns a JSON object. Apps Script intercepts this payload.

{
  "moduleName": "Bookings",
  "fields": [
    {
      "name": "Destination",
      "type": "relation",
      "target": "Destinations"
    },
    {
      "name": "Trip Dates",
      "type": "dateRange"
    },
    {
      "name": "Total Cost",
      "type": "computed",
      "formula": "price_per_person * number_of_travelers"
    }
  ]
}

The script maps this array to physical spreadsheet tabs. It builds a “Bookings_Schema” tab. It places the field names in row 1. It sets the data types in row 2. The web frontend reads these definitions to generate HTML forms dynamically.

How relational fields work

The most demanding part of the prompt is the relational linking. The sentence “Link each booking to a destination and a travel agent” forces Gemini to create relational drop-down menus.

You don’t type the destination name manually. You click a drop-down. The app fetches all the destinations you previously added to the Destinations module. This keeps your database clean and prevents spelling errors.

Step 4: Modifying the app on the fly

Gemini creates 3 new schema sheets in your file. It builds Destinations, Travel Agents, and Bookings. It creates 3 blank data entry sheets to hold the actual records.

But what happens if you forget a field? You don’t have to start over.

Open the AI App Builder dialogue again. Type a simple instruction. “In the booking schema, add a text area field called special requests for custom notes.”

Hit submit. The AI edits the booking schema sheet directly. It drops the new column precisely where it belongs. Refresh the web app. The new “Special Requests” text box appears in your form. To see other automated methods, read how to use AI for everyday tasks.

Step 5: Handling image and document uploads

File storage breaks most spreadsheet databases. You can’t paste a JPG directly into a cell.

This architecture uses a base64 encoding script. When a user uploads a profile picture, the browser converts the image into a long text string.

The frontend sends this string to Apps Script. The backend decodes the string. It saves the actual JPG file to a public Google Drive folder. It grabs the file URL. It bolts that URL to the spreadsheet cell.

The web app reads the URL and renders the image on the dashboard. Your spreadsheet stays lightweight.

Step 6: User management and invitations

A standalone app fails if nobody else can log in. This system includes a complete user authentication workflow.

Log into the web interface using the Owner account. In the sidebar, click “Send Invitation”. Enter a colleague’s email address and assign them a “Standard” role. Click send.

The Apps Script backend triggers an email to your colleague. It sends a unique invitation code and a direct link. They click the link, land on a sign-up page, and set a password.

They can immediately start booking trips. They can’t access the super-admin settings.

Step 7: Debugging common Apps Script errors

You will hit errors. Web browsers block unverified cross-origin requests. Google Apps Script requires specific CORS headers.

If the web app shows a blank screen, open the Chrome developer tools. Click the Console tab. Look for red text.

A “CORS policy” error means you forgot to set the deployment access to “Anyone”. Go back to the Apps Script editor. Create a new deployment. Set the access correctly.

An “Exception: Daily quota exceeded” error means you ran too many automated tasks. Wait 24 hours for the quota to reset. Batch your database reads to prevent this issue. Don’t read the spreadsheet cell-by-cell. Read the entire data range into memory at once.

Deploying your first spreadsheet build

Building an app used to take weeks of planning. You structured a database and routed APIs. Now, you paste an API key into a spreadsheet. You write a paragraph of instructions. The system handles the rest.

Use this as a testing ground for internal business tools. Spin up an inventory tracker in 5 minutes. Build a client CRM before your morning coffee gets cold. Write a detailed prompt. Watch your spreadsheet turn into real software.

Ready for more? Learn how to build web apps with Cursor AI

Written by Mangaleswaran

Mangaleswaran is the founder of AIZnap (aiznap.com) and a dedicated AI content creator. With a background in blogging and technology, he has a deep passion for making artificial intelligence accessible to everyone. He specializes in breaking down complex AI tools, tutorials, and updates into simple, practical guides that anyone can follow. Whether you are a complete beginner or someone looking to use AI to build websites, apps, or grow your online presence — Mangaleswaran's content is designed to help you take action with confidence.

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