How I built this chatbot in 6 hours

The stack, the cost, and what your version could look like.

2:30 walkthrough — the chat answers menu, hours, and party questions live.

6 hrs

Build time

$1.40

Setup cost

~$2/mo

Running cost

<800ms

Avg response

What it does

The chat assistant on the home page answers questions about Lou's Pizza - menu items, prices, hours, allergens, dietary options, party catering, parking, the whole deal. It's grounded in a single knowledge file so it can't make things up. If it doesn't know, it gives you the phone number.

The point: a buyer who lands on Lou's website at 11pm on a Tuesday gets answers immediately instead of waiting until morning. For a small shop, that's the difference between an order and a closed tab.

The stack

Frontend STATIC Hand-written HTML/CSS/JS, no framework, no build step. Mobile-first.
Hosting AWS S3 bucket + CloudFront CDN. Custom domain on Route 53 with ACM SSL.
API AWS Lambda function (Node.js) behind API Gateway HTTP endpoint.
AI CLAUDE Anthropic Claude Haiku 4.5 with prompt caching - the menu/hours system prompt caches for 5 minutes, dropping cost ~85% per repeat question.
Knowledge FILE Single markdown file (the "knowledge base") that defines everything the bot can say. Edit the file, redeploy, done.
Rate limiting BUILT-IN Per-IP cap of 30 messages per 5 minutes inside the Lambda. Stops abuse without external services.

Cost breakdown

Per month at modest traffic (a few hundred conversations):

S3 + CloudFront: under $1 (mostly free tier)
Lambda + API Gateway: under $0.50 (free tier covers most of it)
Claude API: ~$0.50-$2 depending on conversation volume - cache hits are nearly free
Domain: $3/year (.click TLD)

At 10,000 conversations/month it'd be roughly $8-12. Scales linearly with usage and there's no fixed monthly fee.

Why this beats a generic chat widget

Brand-true. The assistant sounds like Lou's, not like ChatGPT in a box. Tone is in the system prompt.
Won't hallucinate prices or hours. Grounded in the knowledge file. If it's not in the file, it doesn't claim to know.
Yours forever. Lives on your AWS account, not a SaaS subscription. No vendor can pull the plug or jack the price.
Updateable in 30 seconds. Edit one markdown file, run one deploy command, done.

How long for your version

Most small-business chatbots take me 4-8 hours total:

~1 hour to nail your knowledge base (menu, services, hours, FAQ)
~2 hours to brand the chat UI to match your site
~2 hours for backend deploy and testing
~1 hour for handoff (Loom video, README, AWS access)

Typical fixed price: $500-$1,500 depending on scope. Hosted on your AWS account so you own everything end to end.

Want one for your shop?

Find me on Upwork or send a note - I'll give you a fixed quote in 24 hours.

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