Community forum: what to build it with and what it costs
Threads, replies and votes, with moderation tools, email notifications and pages search engines can find.
Sample PRD
- Threads and replies
- Voting
- Moderation tools
- Email notifications
- Search
What it needs
- Email and password sign-in: members have accounts
- Google sign-in (nice to have): sign in with Google
- Postgres: threads and replies
- Transactional email: reply notifications and digests
- Product analytics (nice to have): see which topics are active
MVP: about 100 users, $0/mo
Someone with an idea or a solo founder. Built with an AI app builder: describe it and it builds and hosts it.
| What | Pick | Monthly |
|---|---|---|
| AI coding agent | Base44 Starter | $16 |
| Mailgun Free | $0 | |
| Analytics & errors | PostHog Free | $0 |
Growth: about 10,000 users, $42.10/mo
A funded team or one with traction. Built with an AI coding agent for each of about 3 developers.
- Error tracking: know when something breaks
- Daily backups: daily backups once real people depend on it
| What | Pick | Monthly |
|---|---|---|
| AI coding agent | Augment Code Standard | $20 |
| Hosting | Heroku Basic dyno | $7 |
| Database | DigitalOcean Managed PostgreSQL Single node (1 vCPU, 1 GiB RAM, 10 GiB disk) | $15.15 |
| Sign-in | Auth0 Free | $0 |
| SendGrid Essentials 50k | $19.95 | |
| Analytics & errors | PostHog Pay as you go | $0 |
First cost jump: PostHog for Startups credits for early-stage companies (amount and conditions to verify). expires with credit unused
Scale: about 100,000 users, $154.37/mo
An established product. Built with an AI coding agent with team billing and admin for about 10 developers.
- Error tracking: know when something breaks
- Daily backups: daily backups
- Point-in-time recovery: restore to any minute after a bad deploy
- Multi-factor authentication: two-factor sign-in for accounts worth stealing
| What | Pick | Monthly |
|---|---|---|
| AI coding agent | Augment Code Standard | $20 |
| Hosting | Fly.io Machine, shared-cpu-1x with 256MB RAM | $82.19 |
| Database | DigitalOcean Managed PostgreSQL Single node (1 vCPU, 1 GiB RAM, 10 GiB disk) | $17.30 |
| Sign-in | WorkOS AuthKit | $0 |
| Amazon SES A la carte | $15 | |
| Analytics & errors | Sentry Team | $39.88 |
First cost jump: DigitalOcean Managed PostgreSQL: Single node (1 vCPU, 1 GiB RAM, 10 GiB disk) limits reached, upgrade to Single node (1 vCPU, 2 GiB RAM, 30 GiB disk)
What drives the cost
- Notification and digest emails
- Database reads as threads grow
- Search, if you add a search service
Lock-in
Low if you keep posts in your own database.
Use this in Claude (with Kong Reviews connected at https://kongreviews.com/mcp)

