Solo SaaS MVP Stack

Solo SaaS MVP Stack — AI-Executable Build Brief

You are helping a solo developer or founder ship a production SaaS from scratch. Follow this brief exactly.

What you are building

A full-stack SaaS application with:

• Server-side rendered pages (Node.js + Express + EJS)
• PostgreSQL database for persistent data
• Admin panel for content management
• Transactional email (Resend)
• Deployed to Railway, DNS via Cloudflare

Development environment setup (do this first)

Install these Claude Code tools before writing any code:

1. gstack — workflow skills

git clone --single-branch --depth 1 \

https://github.com/garrytan/gstack.git \

~/.claude/skills/gstack && \

cd ~/.claude/skills/gstack && ./setup

2. ECC — agent harness (inside Claude Code)

/plugin marketplace add \

https://github.com/affaan-m/everything-claude-code

/plugin install everything-claude-code@everything-claude-code

/reload-plugins

3. andrej-karpathy-skills — coding behavior (inside Claude Code)

/plugin marketplace add forrestchang/andrej-karpathy-skills

/plugin install andrej-karpathy-skills@karpathy-skills

/reload-plugins

Infrastructure setup (do this before building)

Railway (hosting):

• Create new Railway project
• Add PostgreSQL plugin — copy DATABASE_URL
• Create services as needed (website, cms, etc.)
• Set root directory per service in Railway settings
• Enable auto-deploy from GitHub main branch

Resend (transactional email):

• Create account at resend.com
• Verify your domain (add DNS records in Cloudflare)
• Create API key — save as RESEND_API_KEY
• Send from: [email protected]

Cloudflare (DNS):

• Add your domain to Cloudflare
• Use Railway one-click DNS setup when adding custom domain
• Keep orange cloud (proxied) for web traffic
• Use grey cloud (DNS only) for any subdomains serving

LLM requests (avoids 100s timeout)

Architecture pattern to follow

Services:

• website/ — public-facing Express + EJS app (port 3001)
• cms/ — admin panel Express + EJS app (port 3002)
• Both connect to the same PostgreSQL database
• Website reads published content only
• CMS reads and writes all content

Database pattern:

• Run CREATE TABLE IF NOT EXISTS on every service startup
• Use connection pooling (max 5 connections per service)
• SSL in production: { rejectUnauthorized: false }
• Seed config tables with ON CONFLICT DO NOTHING

Authentication pattern (CMS):

• Query param ?key=ADMIN_SECRET on all /admin routes
• Middleware checks process.env.ADMIN_SECRET
• Wrong or missing key returns 401 page
• Never redirect, just block

Environment variables (website):

PORT=3001

DATABASE_URL=<Railway PostgreSQL connection string>

NODE_ENV=production

SITE_URL=https://yourdomain.com

RESEND_API_KEY=<your Resend API key>

[email protected]

[email protected]

Environment variables (cms):

PORT=3002

DATABASE_URL=<same Railway PostgreSQL connection string>

NODE_ENV=production

ADMIN_SECRET=<strong random secret>

Build workflow (use ECC commands in this order)

1. /plan-eng-review

Run first. Produce complete file structure, all routes,

database schema, env vars, Railway config.

Wait for approval before writing any code.

2. /feature-dev

Build in this order:

- Database migration (CREATE TABLE IF NOT EXISTS)

- CMS service (admin CRUD)

- Website service (public pages)

- railway.toml for each service

- docker-compose.yml for local testing

3. /review

Full code review before any deploy.

Check: no secrets in code, parameterized queries only,

error handling on all database calls, health check

endpoints on each service.

4. /qa

Test all routes, all admin functions, all database

operations. Use curl for API endpoints.

Verify health checks pass.

5. Deploy

git push origin main

Railway auto-deploys from main branch

Add custom domain in Railway

Use Cloudflare one-click DNS setup

Known gotchas

• Cloudflare 100s timeout kills long LLM requests —

use DNS-only (grey cloud) for LLM-serving subdomains

• Session persistence breaks on Railway restarts —

use connect-pg-simple backed by PostgreSQL

• Subpath proxying causes cookie domain mismatches —

use subdomains instead

• Cloudflare + Railway custom domain: use Railway

one-click Cloudflare setup to avoid DNS conflicts

• Race conditions on concurrent writes — use UNIQUE

constraints + ON CONFLICT DO NOTHING

Proof this works

repoverifier.dev was built using exactly this stack.

Live at https://repoverifier.dev