APP IDEA #19 · AI + GOOGLE WORKSPACE

SheetAI — turning "explain what you want" into a working spreadsheet formula

Built by an Indian solo founder (IndianAppGuy) as one product in a $111K+ revenue portfolio of small, focused tools. SheetAI itself just does one thing: type what you want in plain English, get the exact formula back, inside the sheet. Here's how it works, and the weekend plan to build your own version.

$111K+

Founder's total portfolio revenue (7 products, TrustMRR)

Products shipped by one solo founder

$8/mo

SheetAI's entry paid tier

90+

Languages supported

01 / HOW IT WORKS

What the app actually does

SheetAI installs as a Google Sheets add-on. Instead of remembering VLOOKUP or INDEX/MATCH syntax, the user describes what they want in plain English and gets a working formula back — plus a handful of AI functions that run directly inside cells.

User opens the SheetAI sidebar inside any Google Sheet

Extensions → SheetAI → Launch. No new tab, no new app to learn — it lives where the work already happens.

They type the request in plain language

"Sum all sales from Q4 where salesperson is John" or "flag rows where stock is below reorder level" — no formula syntax required.

AI converts it into the exact formula and drops it in

A working VLOOKUP, INDEX/MATCH, or nested IF appears in the cell, ready to use — not just explained, actually inserted.

Custom functions extend it further

=SHEETAI() for AI-generated text inside any cell, =SHEETAI_EXTRACT() to pull structured data out of messy text, =SHEETAI_CLASSIFY() for sentiment/category tagging — all running as native formulas.

02 / INDIA POTENTIAL

Does this work as an India play

This one's already proven domestically — SheetAI's own founder builds from India. The opening isn't "does this work here," it's "what's still missing for the Indian SMB/accounting market specifically."

63M+

MSMEs in India, most still running accounts, inventory, and billing in Excel or Google Sheets, not dedicated software.

Hindi+

A version that accepts formula requests in Hindi/Hinglish ("Q4 ka total sales nikaalo") is a gap SheetAI's English-first product doesn't fully cover.

GST

Pre-built formula templates for GST returns, HSN code lookups, and invoice reconciliation would target a need generic AI formula tools don't know exists.

₹299/mo

Realistic India-priced subscription vs SheetAI's $8 (~₹670) — a rupee-first price point opens the SMB/accountant segment, not just English-speaking tech users.

03 / THE WEEKEND BUILD

Friday to Sunday, hour by hour

Scoped to one core function — text-to-formula — plus a Hindi/Hinglish input mode as the India-specific differentiator. A working, privately-usable add-on is realistic in a weekend; public Google Workspace Marketplace approval takes longer (more on that in deploy).

Friday

Evening · 3 hrs

7–8 PM Set up a Google Apps Script project bound to a test Sheet, scaffold the sidebar UI with HtmlService.

8–9 PM Build a simple backend endpoint (Vercel serverless function) that takes a text prompt and calls Gemini/GPT to return a formula string.

9–10 PM Connect the sidebar to that endpoint — type a request, see a formula come back as plain text first.

Saturday

Full day · 7 hrs

Morning Make the formula actually insert into the selected cell using SpreadsheetApp.getActiveRange().setFormula(), not just display as text.

Afternoon Add the Hindi/Hinglish input handling — detect script, prompt the AI to still output standard formula syntax regardless of input language.

Evening Build 2–3 custom functions like =SHEETAI() equivalents for free-text generation directly in cells.

Sunday

5 hrs

Morning Add usage limits and a simple Razorpay-based upgrade flow (free tier: 20 formulas/month, paid: ₹299/month unlimited).

Afternoon Build 5 pre-made GST/HSN/invoice formula templates as one-click buttons in the sidebar — your India-specific hook.

Evening Test end-to-end on a real messy spreadsheet, record the demo for your first post.

04 / APP STACK

What you're actually building with

Google Apps Script

The add-on itself

Runs inside Google's environment, gives direct access to the active sheet, range, and cell via SpreadsheetApp.

Html

HtmlService (sidebar UI)

Frontend

Apps Script's built-in way to render a sidebar panel — plain HTML/CSS/JS, no separate hosting needed for the UI.

Vercel serverless function

AI backend

A lightweight endpoint that takes the text prompt, calls the AI model, and returns a clean formula string.

Gemini API

Text-to-formula + Hindi parsing

Strong at both code-like formula generation and Hindi/Hinglish understanding in one model.

Razorpay

Payments

UPI-first ₹299/month subscription — works inside the Apps Script UI via a simple checkout link.

PropertiesService

Usage tracking

Apps Script's built-in key-value store — enough to track free-tier formula counts per user without a separate database.

05 / WHERE & HOW TO DEPLOY

Going live

Honest heads up: the AI backend deploys in a weekend like any normal app. Listing publicly on the Google Workspace Marketplace, though, requires a Google review that typically takes 1–2 weeks — so the weekend goal is a fully working add-on you can already demo and personally use, with the public listing as the very next step after.

Deploy the AI backend to Vercel first — same flow as any Next.js/serverless project, gives you a live API endpoint.

In the Apps Script editor, go to Deploy → Test deployments to use the add-on yourself immediately, without waiting on any review.

Share the script with a few friends/early testers via Deploy → Manage deployments → Test so they can install it too, fully working, pre-public-listing.

Once you've validated it works and want public distribution, register a Google Cloud project, fill out the Workspace Marketplace SDK listing form, and submit for review.

While that review runs, keep growing through direct demo videos and shared test links — you don't need to wait on Google to start showing it off.

06 / MARKETING & REVENUE

Getting paying users

How to market it

Post the "messy formula → typed in plain Hindi → instant working formula" demo as a reel — the contrast is the entire hook.
Run 10–20 reels/day across multiple accounts targeting different angles: accountants, Excel power users, small business owners, students.
List directly on the Google Workspace Marketplace once approved — built-in discovery from people already searching "AI Sheets" inside Google's own store.
Partner with a few CA (Chartered Accountant) firms or Tally consultants for a free trial in exchange for GST-formula-template feedback.
Free tier (20 formulas/month) as the hook, paid tier removes the cap — classic freemium that needs zero convincing copy.

Who pays, and why

Small business owners and accountants who live in Excel/Sheets daily but never learned formula syntax.
College students and early-career analysts who need to look formula-fluent fast.
Operations and finance teams at small companies still doing manual GST/invoice reconciliation by hand.

Scenario

Paying users/mo

Revenue/mo

Slow start

60 users × ₹299

₹17,940

Marketplace listing live + steady reels

500 users × ₹299

₹1,49,500

10–20 reels/day (multi-account) + CA firm partnerships

2,800 users × ₹299

₹8,37,200

07 / START BUILDING

Paste this into Claude or GPT

This prompt sets up the full build context so the AI scopes, plans, and starts coding the project with you from message one.

BUILD_PROMPT.txt

I want to build a Google Sheets AI add-on for the Indian market, inspired by SheetAI.app, scoped to ship a working version in a single weekend. Core flow: 1. User opens a sidebar inside Google Sheets (via Apps Script + HtmlService) and types what they want in plain English OR Hindi/Hinglish. 2. A backend AI call (Gemini API) converts that into a working spreadsheet formula. 3. The formula gets inserted directly into the currently selected cell using SpreadsheetApp. 4. A few custom functions (like =SHEETAI() equivalents) also work directly inside cells for free-text generation. 5. Include 5 pre-built one-click templates for common Indian business formulas: GST calculation, HSN code lookup, invoice reconciliation, late payment interest, and stock reorder alerts. Stack I want to use: Google Apps Script (the add-on itself, using SpreadsheetApp and HtmlService), a Vercel serverless function as the AI backend, Gemini API for formula generation and Hindi/Hinglish parsing, Razorpay for a ₹299/month subscription unlock, PropertiesService for tracking free-tier usage limits (20 formulas/month free). Help me, step by step, one question at a time: 1. Scope the Apps Script project structure — sidebar HTML, server-side functions, and how they connect to the external AI backend. 2. Build the core loop first: sidebar input → backend AI call → formula returned as plain text. Get this working before inserting into cells. 3. Add the logic to insert the returned formula into the actively selected cell. 4. Build the Hindi/Hinglish input handling so requests in either language still produce standard formula syntax output. 5. Add the 5 pre-built India-specific formula template buttons. 6. Wire up Razorpay and PropertiesService-based usage limits for the free/paid split. 7. Walk me through using Test Deployments so I can use and share the add-on immediately, and explain what's needed later for public Workspace Marketplace listing. Keep explanations short and India-context aware — UPI payments, ₹-priced, and Hindi/Hinglish language handling as a first-class feature, not an afterthought. Push me to ship the smallest working version first, then improve it. If I get stuck on anything, tell me directly to ask @buildwithkanhaa for the next step or a fresh app idea.