(field notes · Shipping lean · )

Build AI.
Ship lean.

Microsoft's AI costs now exceed its payroll. You don't need their budget — you need the right workflow. Here's how to ship a real AI product this weekend for under $20.

  • Field notes
  • ~10 min read
  • 4 build types
  • 19 steps

Microsoft's AI costs now exceed its payroll. You don't need their budget — you need the right workflow.

This is a build guide, not an essay. Four tools, four build types, the exact prompts to paste into Claude Code, the mistakes that waste a weekend, and what all of it actually costs. Everything below fits into two days and about twenty dollars of API credit.

01The context

Enterprise AI now costs more than the employees it replaced

Microsoft's internal AI spending exceeded its human workforce costs this year. Uber burned through their entire 2026 AI tools budget in just four months. A VP at Nvidia said it plainly: "The cost of AI for my team was more than humans."

Why the bills look like that

These companies are bleeding money because they're using AI like a department — thousands of licences, enterprise SLAs, managed infrastructure.

The builders who win aren't the ones with the biggest budget. They're the ones who've learned to build lean.
Enterprise cost · $$$

Copilot licences at scale. Managed compute. Vendor lock-in. Costs that compound with every seat, every API call, every team that needs access.

Your build cost · ~$20

Claude Code + Replit free tier + Supabase free tier. One weekend. One deployed, working product. No procurement. No DevOps team.

02The lean stack

Four tools. Every AI product you can imagine.

No tool tourism. Each one earns its place by shipping real outcomes — used together, they replace an entire engineering team for prototype-to-MVP work.

ToolLayerWhat it does
Claude CodeAI layerYour AI co-developer. Writes, debugs, and iterates on code from plain-English instructions. Replaces hours of Googling.
ReplitIDE + deployBrowser-based dev environment with one-click deploy. No local setup, no Docker, no server configuration.
SupabaseDatabasePostgres database + auth in minutes. Free tier handles thousands of rows and concurrent users.
n8nAutomationVisual automation builder. Trigger workflows, connect APIs, build agents — no code required.
03The workflow

Pick your build. Copy the workflow.

Each build type below comes with the exact steps and Claude Code prompts I use. Pick what you're shipping — the workflow adapts.

Four shapes cover nearly everything worth building in a weekend. Step through them to see what each one costs you in time, what it runs on, and what you are left holding when it finishes.

45 min · Claude Code, Replit, Supabase

AI Chatbot

A support bot that remembers the conversation. Six steps: create the Repl, add the key as a secret, scaffold the whole app with one prompt, debug by describing the failure, move storage to Supabase, deploy.

Output

Deployed chatbot with conversation memory. Live URL. Shareable.

30 min · n8n Cloud, Claude API

Automation

No code at all. A trigger, an HTTP request to Anthropic, and a destination node. Five steps from signing up to something that runs itself every morning.

Output

A workflow running on schedule, 24/7, zero maintenance.

One weekend · Claude Code, Replit, Supabase

Full MVP

A real product: one-sentence spec, one scaffold prompt, an hour of plain-English iteration, then deploy. Four steps, and the last one is shipping before it feels ready.

Output

A shareable, deployed product with real users by Sunday.

90 min · Claude Code, Replit, n8n

AI Agent

An agent takes action rather than answering. One job, one endpoint on Replit, one n8n trigger that hits it on a schedule, one destination.

Output

An agent running 24/7 without you — real actions, real output.

Every step, prompt and rule from all four workflows is written out in full below. Nothing is hidden behind a tab.

04Build 01

AI Chatbot, deployed in 45 minutes

Forty-five minutes, three tools, one deployed chatbot that remembers the conversation.

Build 01 · 45 min

AI Chatbot

Claude Code · Replit · Supabase. Deployed chatbot with conversation memory. Live URL. Shareable.

UI APP LLM DB MESSAGE CLAUDE API MEMORY browser replit anthropic supabase

01 · Open Replit — create a Node.js Repl

3 min. Go to replit.com → New Repl → Node.js template. Name it. This is your full dev environment — no installs, no config.

02 · Add your Anthropic API key as a Secret

2 min. Tools → Secrets → Add ANTHROPIC_API_KEY. Never hardcode keys in files.

Replit secret
ANTHROPIC_API_KEY = sk-ant-api03-...

03 · Prompt Claude Code to scaffold the full app

5 min. Hit the AI button in the Replit sidebar. Paste this exact prompt.

Claude Code prompt
Build a customer support chatbot web app.
- Uses Anthropic API (key in env: ANTHROPIC_API_KEY)
- Reads FAQ from a hardcoded JS array
- Keeps conversation history in memory per session
- Clean chat UI (white bubbles, dark bg)
- Express.js backend, vanilla JS frontend
Run on port 3000.

04 · Debug by describing the problem to Claude

10 min. When something breaks, don't Google it. Tell Claude what happened.

Debug prompt pattern
The chatbot replies but loses history after each message.
Expected: context should persist across the full session.
Error: [paste exact error here]
Fix this.
The rule

Never say "it doesn't work." Always say what you expected, what happened instead, and paste the exact error. Claude fixes it in one shot.

05 · Connect Supabase for persistent storage

10 min. Create a free Supabase project → grab URL + anon key → add as Replit Secrets → ask Claude Code to upgrade.

Upgrade prompt
Replace in-memory storage with Supabase.
- SUPABASE_URL and SUPABASE_KEY already in env
- Create table: conversations
  columns: id, session_id, role, content, created_at
Store every message. Load full history on session start.

06 · Deploy — one click, live URL

2 min. Replit Deploy button → your app is live at a public URL. No DevOps. Share it. You shipped.

Total cost

~$20 in API credits. Supabase free tier. Replit free tier. The same thing costs enterprises thousands per month.

The only hard part is step four, and it is a habit rather than a skill: describe the failure instead of naming it.

05Build 02

Automation that runs without you

Thirty minutes, no code, and a workflow that keeps running after you close the tab.

Build 02 · 30 min

Automation

n8n Cloud · Claude API. A workflow running on schedule, 24/7, zero maintenance.

S F AI OUT 8AM POST SEND schedule source claude slack ACTIVATE ONCE · RUNS FOREVER

01 · Sign up for n8n Cloud (free tier)

3 min. n8n.io → Start free. Visual workflow builder — every node is drag and drop. No code required.

02 · Set your trigger

5 min. What starts the workflow? Schedule (runs every X hours), Webhook (URL hit), or Gmail (new email arrives).

Best first automation

Schedule trigger (8am daily) → fetch top AI news → Claude summarises in 3 bullets → sends to Telegram or Slack.

03 · Add HTTP Request node → Anthropic API

8 min. Add HTTP Request node. Configure as POST to Anthropic.

n8n HTTP Request config
URL: https://api.anthropic.com/v1/messages
Method: POST
Headers:
  x-api-key: YOUR_KEY
  anthropic-version: 2023-06-01
  Content-Type: application/json
Body:
{
  "model": "claude-sonnet-4-20250514",
  "max_tokens": 500,
  "messages": [{"role":"user","content":"Summarise in 3 bullets: {{$json.content}}"}]
}

04 · Route output to Slack, Telegram, or Sheets

5 min. Add final node. Map {{$json.content[0].text}} as your message body. That's the AI response.

05 · Activate — runs forever, for free

2 min. Execute once to test → if it passes, toggle Active. Your automation now runs on schedule with no maintenance.

What you built

The same thing consultants charge £50k to deliver. You did it in 30 minutes.

Every node above is drag and drop. The only text you write is the prompt inside the HTTP request body.

06Build 03

A full MVP in one weekend

One weekend, one spec sentence, one scaffold prompt, and an hour of iteration in plain English.

Build 03 · one weekend

Full MVP

Claude Code · Replit · Supabase. A shareable, deployed product with real users by Sunday.

1 2 3 4 ITERATE SCAFFOLD RUN SHIP spec skeleton edge cases deploy SHIP BEFORE IT IS PERFECT

01 · Write a one-sentence spec before touching code

10 min. Fill in: "A web app that lets [WHO] [DO WHAT] so that [OUTCOME]." Nothing vague.

Spec template
A web app that lets [founders]
[paste a company URL and get an AI-written cold email]
so that [they save 30 min per outreach target].

02 · Scaffold the full stack in one Claude Code prompt

15 min. One detailed prompt. Get the whole skeleton — backend, frontend, database, API calls.

MVP scaffold prompt
Build a full-stack MVP: paste URL → AI-written cold email.

Stack: Express.js + Vanilla JS + Anthropic + Supabase
All keys already in Replit env.

Pages:
1. Home — URL input + Generate button
2. Result — email output + Copy button

System prompt for Claude:
"You are a B2B sales expert. Write a cold email.
 Max 150 words. Subject line + body."

Store: input_url, email_output, created_at in Supabase.
Port 3000.

03 · Iterate in plain English — UI, logic, edge cases

60 min. Each round of changes = one Claude Code message. Be specific about what you want.

Iteration examples
// Round 1 — UI
Dark bg, white card result, mobile responsive.

// Round 2 — UX
Add loading spinner while email generates.

// Round 3 — Edge case
If URL scrape fails, show friendly error.
Do not crash the app.

04 · Deploy and share before it's perfect

5 min. Replit Deploy → live URL. Share with 5 people before adding another feature. Real feedback beats more code.

The rule

Ship when 3 people can complete the core action without you explaining it. Not when it's perfect.

Notice how little of that weekend is spent typing code. Most of it is spent deciding what the thing is and then correcting it out loud.

07Build 04

An AI agent that takes action

Ninety minutes for something that takes action on its own: one job, one endpoint, one schedule.

Build 04 · 90 min

AI Agent

Claude Code · Replit · n8n. An agent running 24/7 without you — real actions, real output.

S RSS API OUT LLM 8AM TOP 10 TOP 3 PICKS your endpoint n8n reddit slack claude

01 · Define the one job the agent does

10 min. Agent = AI that takes action, not just answers. Decide: trigger → action → output. Keep it one job.

Best first agent

Every morning → scrape 10 Reddit posts from your niche → Claude picks top 3 → posts summary to your Slack.

02 · Build the action endpoint on Replit

20 min. Claude Code builds the API endpoint — receives data, calls the AI, returns a result. This is the agent's brain.

Agent endpoint prompt
Build a POST endpoint at /agent/summarise.

Input: { "posts": ["post1...", "post2..."] }

System prompt for Claude:
"Pick the 3 most insightful posts for AI builders.
 Return JSON: [{title, why_relevant, url}]"

Return Claude's parsed JSON.
Express.js. Key in env: ANTHROPIC_API_KEY. Port 3000.

03 · Wire the trigger in n8n

20 min. Schedule trigger → RSS/API source → HTTP POST to your Replit endpoint → Slack send.

n8n agent flow
Schedule (8am daily)
  → RSS: reddit.com/r/MachineLearning.rss
  → Code node: extract top 10 titles + links
  → HTTP POST: your-repl.replit.app/agent/summarise
  → Slack: #ai-news → {{$json.content}}

04 · Deploy as Always On — runs without you

5 min. Replit Deploy → endpoint stays live 24/7. n8n hits it on schedule. The agent runs forever without you touching it.

What you built

A 24/7 AI agent doing the job that would take a junior hire 30 minutes every morning. Automated, free, and fully yours to extend.

The endpoint is the brain and n8n is the alarm clock. Keep them separate and either one can be replaced without rebuilding the other.

08Watch out

Four mistakes that kill first builds

Most builders hit the same walls. Knowing where they are is half the fix. Open any row for what actually goes wrong.

"Make it better" or "fix the bug" gives Claude nothing to work with. Name exactly what broke, what you expected, and paste the error. Precision = speed.
Adding features before anyone has used v1 is the fastest way to waste a weekend. Ship the core action first. Add features to things people actually use.
Replit has quirks. Supabase has gotchas. Spend 20 minutes reading the docs for each tool once — then stop re-learning and start building.
The number one cause of wasted build time is starting without a clear spec. One sentence: who does what so that outcome. Write it before you open Replit.
09So what

What this means if you're building

If you're building in the AI space, the current landscape is a tale of two worlds: bloated enterprise suites vs. lean, modular stacks. Here's what actually determines who wins.

Point 01

Speed is the only defensible moat

Enterprise AI is paralyzed by procurement, compliance, and multi-departmental sign-offs. If you are building lean, your advantage isn't just cost — it's the ability to ship, fail, and iterate while they are still drafting the project charter.
Point 02

Leverage > Feature Count

Don't try to build the next platform. Use tools like Claude Code and n8n as force multipliers. One person with the right workflow can output more functional code in a weekend than a 10-person enterprise team burdened by meetings and legacy debt.
Point 03

Modularity prevents vendor lock-in

Enterprise stacks are designed to trap you in an ecosystem. By building on portable infrastructure like Supabase and Replit, you remain agile. If a vendor changes their pricing, you have the flexibility to pivot without re-platforming your entire business.
Point 04

Shipping value beats building hype

Enterprise AI often focuses on building "AI features" that don't solve user problems. You are building solutions. When you ship lean, you aren't just saving money — you are forced to focus on the one thing that actually delivers value to the end user.
10Your move

Build with AI. Understand what you're building.

Deep technical breakdowns, build walkthroughs, and real AI product tutorials — for founders, operators, and developers who want to stay on the right side of the gap.

Microsoft's bill is not your bill. The stack above costs about twenty dollars and a weekend, and it ends with a URL you can send to someone.

Haroon K M · @ closefuture · haroon.pro. Share this piece with whoever told you AI was too expensive to build with.

(Your turn)

What would you ship this weekend if the entire budget was twenty dollars, two days, and one sentence describing who it is for?

  • #AI
  • #ClaudeCode
  • #Replit
  • #Supabase
  • #n8n
  • #AIWorkflow
  • #ShipLean
  • #BuildInPublic
  • #IndieHackers
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