Hi Friends,

Even as I launch this today ( my 80th Birthday ), I realize that there is yet so much to say and do. There is just no time to look back, no time to wonder,"Will anyone read these pages?"

With regards,
Hemen Parekh
27 June 2013

Now as I approach my 90th birthday ( 27 June 2023 ) , I invite you to visit my Digital Avatar ( www.hemenparekh.ai ) – and continue chatting with me , even when I am no more here physically

Thursday, 29 January 2026

COST BREAK UP

 Kishan ,

 

During my yesterday’s chat with RO.app , it mentioned some monthly cost estimates. Just now, I asked it to clarify through a break up. Here is that answer :

 

[  Kishan >  I suppose , you can calculate “ Estimated Income ( @ Rs 20 per document generated ) “ for those different “ Monthly User Activity Levels “ . ]

 

 

Thought for 2s

 

Excellent question, Hemen Bhai!  Let me break down the detailed cost estimation for 500 daily active users:


Cost Breakdown for 500 DAU (Daily Active Users):

 

1. WhatsApp Business API

·          

·         Per message cost: $0.0079 per template message (India pricing)

·          

·         Daily alerts: 500 users × 1 alert/day = 500 messages/day

·          

·         Monthly: 500 × 30 × $0.0079 = $118.50/month

·          

·         Note: Only charged for messages sent OUT, not received

 

 

2. LLM API (Document Generation)

·          

·         Average document: ~500 tokens to generate

·          

·         API cost (using Vercel AI Gateway/Claude): ~$0.003 per 1K tokens

·          

·         Avg cost per document: 500 tokens × ($0.003/1K) = $0.0015

·          

·         Users generating 1 doc/day average: 250 documents/day

·          

·         Monthly: 250 × 30 × $0.0015 = $11.25/month

·          

·          

·         Note: Some users will generate more, some less. This is conservative.

 

 

3. Firebase Cloud Messaging (Push Notifications)

·          

·         Free tier: 100K messages/month included

·          

·         At 500 DAU, 1 notification/day: 500 × 30 = 15K/month

·          

·         Cost: FREE (within free tier)

·          

·         Only pays if exceeds 100K/month

 

 

4. Google Trends API / News API

·          

·         NewsAPI (for trending topics): $0 for 100 requests/day (free tier)

·          

·         Or: $99/month for higher volume if needed

·          

·         Cost: $0-99/month (using free tier initially)

 

 

5. Database Hosting (PostgreSQL)

·          

·         Neon Serverless PostgreSQL: Starting at $0.16/day

·          

·         OR Supabase: $25/month starter plan

·          

·         Estimated usage (500 DAU): ~100 MB data

·          

·         Cost: $25-50/month

 

 

6. Server/Backend Hosting

·          

·         Vercel (Next.js backend):

·          

·         Free tier: 100 GB bandwidth/month

·          

·         At 500 DAU, ~50-100 GB/month = within free

·          

·         If paid: $20/month minimum

·          

·         OR AWS Lambda: Pay per invocation ($0.20 per 1M requests)

·          

·         Estimated: $10-30/month

·          

·         Cost: $0-30/month (free tier sufficient)

 

7. Analytics & Monitoring

·          

·         Sentry (error tracking): Free tier

·          

·         Vercel Analytics: Free

·          

·         Cost: $0/month

 

8. SMS Verification (Phone OTP)

·          

·         Twilio: $0.0075 per SMS in India

·          

·         Estimated: 10% of DAU need re-verification = 50 messages/month

·          

·         Cost: 50 × $0.0075 = $0.375/month

 

 

9. Storage (Generated Documents, Images)

·          

·         Vercel Blob: $0.50 per GB stored

·          

·         Estimated: 500 DAU × 10 docs × 0.5 MB avg = 2.5 GB/month

·          

·         Cost: 2.5 × $0.50 = $1.25/month


Total Monthly Cost Breakdown:

 

Service

Cost

WhatsApp API

$118.50

LLM Document Generation

$11.25

Firebase Notifications

$0

News API

$0

Database (PostgreSQL)

$25-50

Server/Backend Hosting

$0-30

SMS Verification

$0.375

Storage (Blob)

$1.25

SUBTOTAL

$156.40 - $211.40

Contingency (20%)

$31 - $42

TOTAL (Conservative)

~$200-250/month


Why I Said $500-1000?

 

I included buffer for:

1.     

2.    Scaling Safety (2-3x growth): If you hit 1,000-1,500 DAU unexpectedly

3.     

4.    Premium Services: Upgraded Google Trends, better LLM models

5.     

6.    Infrastructure redundancy: Backup databases, failover systems

7.     

8.    Team salary allocation: Part of a developer's time for maintenance

9.     

10.  Unexpected costs: Emergency scaling, API rate limit overages


More Realistic Estimate for 500 DAU:

 

Tier

Cost

Details

Minimum (Lean)

$150-200

Free tiers, basic services

Standard (Recommended)

$250-400

Reliable infrastructure

Premium (Safe)

$500-800

Redundancy, backups, monitoring

Enterprise (Growth)

$1000+

Multiple regions, dedicated support


As You Scale (Revised Estimates):

 

Users

Monthly Cost

500

$200-300

1,000

$300-500

5,000

$600-1,200

10,000+

$1,500-3,000+


My Recommendation for Kishan:

 

Start with $250-300/month budget to cover:

 

·         WhatsApp API ($120)

·          

·         Database ($50)

·          

·         Hosting ($20-30)

·          

·         LLM generation ($10-15)

·          

·         Buffer ($50)

·          

This is realistic and sustainable for 500 DAU with room for growth.

 

Does this breakdown help clarify the calculation, Hemen Bhai?

 

Worked for 21s

 

 

 

I continued but ran out of FREE CREDITS – hence no reply / but I am sure you can calculate to see if this could be a profitable operation :

 

I asked :

 

Hey Bro : That was very detailed and precise , with clear cut " Assumptions " of DAU. Now I wonder if you can also help me figure out " Monthly Income " ( for 500 DAU ) if I were to charge Rs 20 for each document generated . Pl compute all figures in Rupees and show the MARGIN ( Income minus Expenses ) in a tabulation

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