STEMblock Platform - Cost-Optimized Deployment Guide

For Development/Internal Trial Use

Target: Minimal cost deployment for internal testing and trials Platform: Digital Ocean App Platform (maximized usage) Monthly Budget: Under $20/month

Cost-Optimized Architecture
Prerequisites
Database Setup (Dev Tier)
Backend Deployment
Frontend Deployment
Environment Configuration
Cost Breakdown
Scaling Path

Cost-Optimized Architecture

┌─────────────────┐
│   Test Users    │
└────────┬────────┘
         │
         │ HTTPS (Free SSL)
         │
┌────────▼──────────────────────────────┐
│   Digital Ocean App Platform           │
│   (Includes Load Balancer + SSL)       │
└──────┬──────────────────────┬─────────┘
       │                      │
       │                      │
┌──────▼──────────┐  ┌────────▼──────────┐
│   Frontend      │  │   Backend API     │
│   Static Site   │  │   Basic Tier      │
│   $5/month      │  │   $5/month        │
└─────────────────┘  └─────────┬─────────┘
                               │
                               │
                     ┌─────────▼──────────┐
                     │ Managed PostgreSQL  │
                     │ Dev Database        │
                     │ $7/month (with promo)│
                     └────────────────────┘

Total Monthly Cost: ~$17/month

Prerequisites

Required Accounts

Digital Ocean account
GitHub account (for code deployment)
Mistral AI API key (Free tier available)

Cost-Saving Tips

Use Digital Ocean Promo: New accounts get $200 credit for 60 days
- Sign up at: https://www.digitalocean.com/
- This covers ~11 months of dev deployment
Mistral AI Free Tier:
- Use "open-mistral-7b" model
- Free tier: 1M tokens/month
- Sufficient for 100-200 evaluations/month

Database Setup

Option 1: Managed PostgreSQL Dev Tier (Recommended)

Cost: $7/month (with promo) or FREE for first 60 days

Create Database Cluster
- Navigate to: Databases → Create Database Cluster
- Select: PostgreSQL 15
- Choose plan: Dev Database
  - 1 GB RAM
  - 10 GB Disk
  - 1 vCPU
  - $7/month (but FREE with $200 credit)
- Choose datacenter region: New York 3 (cheapest)
- Name: stemblock-db-dev
Security Settings
- Enable "Trusted Sources"
- Add App Platform as trusted source
- Enable connection pooling (free, improves performance)

Connection Details

Host: stemblock-db-dev-do-user-XXXXX-0.b.db.ondigitalocean.com
Port: 25060
User: doadmin
Password: [provided by DO]
Database: defaultdb
SSL: required

Create Application Database

# Connect via psql
psql "postgresql://doadmin:PASSWORD@HOST:25060/defaultdb?sslmode=require"

# Create database
CREATE DATABASE stemblock_dev;
\q

Connection String

postgresql://doadmin:PASSWORD@HOST:25060/stemblock_dev?sslmode=require&schema=public

Option 2: Free PostgreSQL (Alternative)

If you want $0 cost during trial:

Use ElephantSQL Free Tier
- Visit: https://www.elephantsql.com/
- Free plan: "Tiny Turtle"
  - 20MB storage (sufficient for testing)
  - 5 concurrent connections
  - $0/month
Use Supabase Free Tier
- Visit: https://supabase.com/
- Free plan includes:
  - 500MB database
  - 50,000 monthly active users
  - $0/month

For serious testing, we recommend Option 1 (Digital Ocean managed DB with promo credit)

Backend Deployment

1. Prepare Repository

Ensure your code is on GitHub:

cd ~/stemblock
git add .
git commit -m "Prepare for deployment"
git push origin main

2. Create App Platform App - Backend

Navigate to App Platform
- Go to: App Platform → Create App
- Source: GitHub
- Repository: stemblock
- Branch: main

Configure Backend Component

Name: stemblock-backend
Type: Web Service
Source Directory: /backend

Build Command: npm ci && npm run build
Run Command: npm run start:prod

HTTP Port: 8080
HTTP Routes: /

Instance Size: Basic (512MB RAM, 1 vCPU) - $5/month
Instance Count: 1

Health Check:
  HTTP Path: /health
  Port: 8080
  Initial Delay: 30s
  Period: 60s

Add Environment Variables

# Database
DATABASE_URL=postgresql://doadmin:PASSWORD@HOST:25060/stemblock_dev?sslmode=require&schema=public

# JWT (Generate random 32+ char string)
JWT_SECRET=your-secure-random-string-min-32-characters
JWT_EXPIRATION=7d

# App
PORT=8080
NODE_ENV=development
FRONTEND_URL=https://your-app-name.ondigitalocean.app

# File Upload
UPLOAD_DIR=/tmp/uploads
MAX_FILE_SIZE=10485760

# AI Evaluation (Free tier)
LLM_PROVIDER=mistral
MISTRAL_API_KEY=your-mistral-api-key
MISTRAL_MODEL=open-mistral-7b
MISTRAL_MIN_REQUEST_INTERVAL=2000
MISTRAL_MAX_RETRIES=5
LLM_FALLBACK_TO_MOCK=true

# Google OAuth (Optional - leave empty if not using)
GOOGLE_CLIENT_ID=
GOOGLE_CLIENT_SECRET=
GOOGLE_CALLBACK_URL=https://your-api-url/auth/google/callback

Database Migrations Setup

You have TWO options for running database migrations:

Option A: Using Job Component (Recommended)
1. In your app, click Create → Create Resources From Source Code
2. Select your repository and branch
3. In the resource configuration screen, click Edit in the Info section
4. Change resource type to Job (not "Web Service")
5. Configure the Job:
```
Name: db-migration
Type: Job
Source Directory: /backend
Build Command: npm ci
Run Command: npx prisma migrate deploy
Instance Size: Basic (512MB RAM)
```
6. In the When to Run dropdown, select Pre-deploy
7. This ensures migrations run before each deployment
Option B: Run Migrations in Start Command (Simpler Alternative)

If you can't find the Job component option, modify your backend Run Command to:
```
Run Command: npm run start:migrate
```
This runs npx prisma migrate deploy && npm run start:prod automatically.

Note: npx prisma migrate deploy is idempotent (safe to run multiple times).
Create Resources
- Click "Create Resources"
- Wait 5-10 minutes for deployment
- Note the backend URL: https://stemblock-backend-xxxxx.ondigitalocean.app

Frontend Deployment

1. Update Frontend Configuration

File: /frontend/.env.production

NEXT_PUBLIC_API_URL=https://your-backend-url.ondigitalocean.app

Update next.config.js:

/** @type {import('next').NextConfig} */
const nextConfig = {
  reactStrictMode: true,
  output: 'standalone',
  env: {
    NEXT_PUBLIC_API_URL: process.env.NEXT_PUBLIC_API_URL,
  },
}

module.exports = nextConfig

2. Add Frontend Component

In App Platform
- Go to your app
- Click "Create Component"
- Type: Static Site (cheaper than Web Service)

Configure Frontend Component

Name: stemblock-frontend
Type: Static Site
Source Directory: /frontend

Build Command: npm ci && npm run build
Output Directory: .next

HTTP Routes: /

Instance Size: Basic (Static Site) - $5/month

Add Environment Variable

NEXT_PUBLIC_API_URL=https://your-backend-url.ondigitalocean.app

Deploy
- Click "Save"
- Wait 5-10 minutes
- Note the frontend URL: https://your-app-name.ondigitalocean.app

Environment Configuration

Update Backend CORS

After deployment, update FRONTEND_URL in backend environment variables to match your actual frontend URL.

Also update CORS in backend code if needed:

File: /backend/src/main.ts

app.enableCors({
  origin: [
    process.env.FRONTEND_URL,
    'https://your-app-name.ondigitalocean.app',
  ],
  credentials: true,
});

Cost Breakdown

Monthly Costs (Development/Trial)

Service	Tier	Specs	Cost
Database	Dev Database	1GB RAM, 10GB disk, 1 vCPU	$7/month
Backend	Basic Web Service	512MB RAM, 1 vCPU	$5/month
Frontend	Static Site	Basic tier	$5/month
Bandwidth	Included	1TB/month	$0
SSL Certificates	Included	Auto-renewed	$0
Load Balancer	Included	With App Platform	$0
Backups	Not enabled	(Can enable for +$1/month)	$0
Mistral AI	Free tier	1M tokens/month	$0
Total			$17/month

Effective Cost: $0/month for first ~11 months
After Promo: $17/month ongoing

Cost Comparison

Deployment	Monthly Cost	Use Case
Development (This guide)	$17/month	Internal testing, <50 users
Staging	$35/month	User testing, <100 users
Production	$89/month	Live product, 500+ users

Optimization Strategies

1. Minimize Database Costs

Use Dev Database tier ($7/month vs $15+ for Basic)
Only 1 node (no replicas during dev)
No point-in-time recovery (enable in production)
Manual backups when needed

2. Minimize Compute Costs

Backend: Basic tier 512MB RAM ($5/month vs $12+ for Professional)
Frontend: Static Site ($5/month vs $12+ for Web Service)
Single instance each (no auto-scaling)

3. Leverage Free Services

SSL certificates: Included with App Platform
Load balancer: Included with App Platform
Bandwidth: 1TB included (enough for 10,000+ pageviews)
Logs: 7 days retention included
Metrics: Basic monitoring included

4. AI Costs

Use Mistral "open-mistral-7b" (free tier)
Enable response caching (already implemented)
Fallback to mock provider for testing

5. Storage Costs

File uploads to /tmp (ephemeral, free)
For permanent storage, add Spaces later ($5/month for 250GB)

Limitations of Dev Tier

Acceptable for Internal Trial:

✅ Up to 50 concurrent users
✅ Up to 10GB database storage
✅ Up to 1TB bandwidth/month
✅ Basic monitoring and logs
✅ SSL and custom domains

Not Suitable For:

❌ Production workloads
❌ 100+ concurrent users
❌ High-availability requirements
❌ Advanced backups and recovery
❌ Dedicated resources

Scaling Path

When to Upgrade

From Dev to Staging ($17 → $35/month)

Database: Dev → Basic ($7 → $15)
Backend: 512MB → 1GB RAM ($5 → $12)
User Load: 10-50 → 50-100 concurrent users

From Staging to Production ($35 → $89/month)

Database: Basic → Professional ($15 → $60)
Backend: 1GB → 2GB RAM ($12 → $24)
Add Redis cache: $7/month
Add Spaces storage: $5/month
Enable backups: +$7/month
User Load: 100 → 500+ concurrent users

Monitoring & Alerts

Free Monitoring Included

Built-in Metrics:

CPU usage
Memory usage
Bandwidth usage
Request count
Response times
Error rates

Set Up Free Alerts:

Go to App Platform → Monitoring
Create alerts for:
- CPU > 80% for 5 minutes
- Memory > 90% for 5 minutes
- Error rate > 5% for 5 minutes

External Monitoring (Free):

UptimeRobot: Free tier monitors 50 URLs
Healthchecks.io: Free tier for basic checks

Deployment Checklist

Initial Setup

Backend Deployment

Create App Platform app
Configure backend component (Basic $5/month)
Add all environment variables
Setup database migrations (Job component OR start:migrate command)
Deploy and test /health endpoint

Frontend Deployment

Update frontend API URL
Add frontend component (Static $5/month)
Configure build settings
Deploy and test homepage

Post-Deployment

Cost-Saving Tips

During Development (Months 1-2)

Use Promo Credit - Covers everything for free
Mock AI Provider - Use LLM_PROVIDER=mock for testing
Pause Database - Not available for managed DB, but minimal cost
Single Region - Choose closest region only

During Trial (Months 3-6)

Monitor Usage - Check App Platform metrics weekly
Optimize Database - Delete old test data
Cache Aggressively - Already implemented for AI
Limit File Uploads - Keep max file size at 10MB

Before Production (Month 6+)

Plan Upgrade - Review user growth projections
Budget for Scale - $89/month for production tier
Enable Backups - Critical for production
Add CDN - Included with App Platform, no extra cost

Frequently Asked Questions

Q: Can I use a free database?

A: Yes! ElephantSQL (20MB free) or Supabase (500MB free) work for initial testing. However, Digital Ocean Dev Database is recommended because:

Better performance
Managed backups available
Easier scaling path
Free with promo credit for 11 months

Q: What happens after the $200 credit runs out?

A: You'll start paying $17/month. You can:

Continue at this tier for internal use
Upgrade to staging/production tiers
Move to free database options to reduce cost
Pause the app if not actively testing

Q: How many users can this handle?

A: Comfortably supports:

10-20 concurrent users
100-200 total registered users
500-1000 API requests/hour
Sufficient for internal trials and demos

Q: Can I add more features without increasing cost?

A: Yes! The cost is based on compute and database size, not features. All current features work within the $17/month budget.

Q: How do I monitor costs?

Check "Billing" in Digital Ocean dashboard
View "Usage" tab in App Platform
Set up spending alerts in Billing settings
Track AI usage in Mistral dashboard

Support & Resources

Digital Ocean Docs: https://docs.digitalocean.com/products/app-platform/
Pricing Calculator: https://www.digitalocean.com/pricing/calculator
Community Forum: https://www.digitalocean.com/community
24/7 Support: Available with all paid plans

Quick Start Commands

# 1. Prepare code
cd ~/stemblock
git add .
git commit -m "Deploy to Digital Ocean"
git push origin main

# 2. Create database (via DO dashboard)
# Note connection string

# 3. Deploy via App Platform dashboard
# Connect GitHub → Configure → Deploy

# 4. Test deployment
curl https://your-backend-url.ondigitalocean.app/health
# Should return: {"status":"ok","database":"connected"}

# 5. Test frontend
open https://your-frontend-url.ondigitalocean.app

Summary

Total Setup Time: ~30-45 minutes Monthly Cost: $17/month ($0 with promo for 11 months) Suitable For: Internal testing, demos, trials with <50 users Upgrade Path: Clear path to production when ready

This deployment strategy maximizes use of App Platform's included features (SSL, load balancing, CI/CD) while minimizing costs through:

Dev-tier database
Basic-tier compute
Static site frontend
Free AI tier
Included bandwidth and SSL

Perfect for internal trials and early-stage testing! 🚀

Last Updated: November 2025 Version: 2.0 - Cost-Optimized Target Audience: Internal trial deployment

For Development/Internal Trial Use​

Table of Contents​

Cost-Optimized Architecture​

Prerequisites​

Required Accounts​

Cost-Saving Tips​

Database Setup​

Option 1: Managed PostgreSQL Dev Tier (Recommended)​

Option 2: Free PostgreSQL (Alternative)​

Backend Deployment​

1. Prepare Repository​

2. Create App Platform App - Backend​

Frontend Deployment​

1. Update Frontend Configuration​

2. Add Frontend Component​

Environment Configuration​

Update Backend CORS​

Cost Breakdown​

Monthly Costs (Development/Trial)​

With Promo Credit ($200 for 60 days)​

Cost Comparison​

Optimization Strategies​

1. Minimize Database Costs​

2. Minimize Compute Costs​

3. Leverage Free Services​

4. AI Costs​

5. Storage Costs​

Limitations of Dev Tier​

Scaling Path​

When to Upgrade​

Monitoring & Alerts​

Free Monitoring Included​

Deployment Checklist​

Initial Setup​

Backend Deployment​

Frontend Deployment​

Post-Deployment​

Cost-Saving Tips​

During Development (Months 1-2)​

During Trial (Months 3-6)​

Before Production (Month 6+)​

Frequently Asked Questions​

Q: Can I use a free database?​

Q: What happens after the $200 credit runs out?​

Q: How many users can this handle?​

Q: Can I add more features without increasing cost?​

Q: How do I monitor costs?​

Support & Resources​

Quick Start Commands​

Summary​

For Development/Internal Trial Use

Table of Contents

Cost-Optimized Architecture

Prerequisites

Required Accounts

Cost-Saving Tips

Database Setup

Option 1: Managed PostgreSQL Dev Tier (Recommended)

Option 2: Free PostgreSQL (Alternative)

Backend Deployment

1. Prepare Repository

2. Create App Platform App - Backend

Frontend Deployment

1. Update Frontend Configuration

2. Add Frontend Component

Environment Configuration

Update Backend CORS

Cost Breakdown

Monthly Costs (Development/Trial)

With Promo Credit ($200 for 60 days)

Cost Comparison

Optimization Strategies

1. Minimize Database Costs

2. Minimize Compute Costs

3. Leverage Free Services

4. AI Costs

5. Storage Costs

Limitations of Dev Tier

Scaling Path

When to Upgrade

Monitoring & Alerts

Free Monitoring Included

Deployment Checklist

Initial Setup

Backend Deployment

Frontend Deployment

Post-Deployment

Cost-Saving Tips

During Development (Months 1-2)

During Trial (Months 3-6)

Before Production (Month 6+)

Frequently Asked Questions

Q: Can I use a free database?

Q: What happens after the $200 credit runs out?

Q: How many users can this handle?

Q: Can I add more features without increasing cost?

Q: How do I monitor costs?

Support & Resources

Quick Start Commands

Summary