SupplyNest - Bill of Materials Cost Tracker for Makers and Small Manufacturers

Etsy sellers and small-batch manufacturers are calculating COGS in spreadsheets that break every time a supplier raises prices by $0.03. SupplyNest is a live bill of materials tracker that alerts you when component costs shift your margins below target. Build it in a weekend, save a maker from financial blindness.

𝕏 Post Reddit HN

Difficulty

beginner

What is it?

Small-batch physical product makers — candle companies, PCB assemblers, custom furniture builders — manage their bill of materials in Google Sheets. When a supplier raises the price of beeswax, soy wax, or a capacitor, they find out at month-end when margin is already gone. SupplyNest lets makers build a visual BOM with supplier links, auto-pulls prices via manual entry or URL scraping, and fires a Slack or email alert when any component change would push product margin below their floor. The core insight is that makers need margin-aware alerts, not just a spreadsheet replacement. Why buildable now: Cheerio-based price scraping, Supabase, and Resend make a functional price monitor shippable in under 2 weeks.

Why now?

The April 2026 maker economy boom on TikTok Shop and Etsy has pushed thousands of solo product sellers to scale batches without any cost tracking tooling, creating urgent demand for sub-$20/month BOM tools.

▸Visual BOM builder with component rows, quantities, and supplier URL fields
▸Cheerio-based price scraper that checks supplier URLs on a configurable schedule
▸Margin calculator that shows real-time COGS and gross margin per product
▸Resend email and Slack alert when any component price change breaches margin floor

Target Audience

Small-batch physical product makers and Etsy power sellers with 10+ SKUs, estimated 500,000 US-based based on Etsy's reported active seller count.

Example Use Case

Jake makes custom mechanical keyboards in batches of 50 and tracks 40 components per board. SupplyNest alerts him when his switch supplier raises prices 8%, letting him update his Etsy listing price before selling the next batch at a loss.

User Stories

▸As a candle maker, I want alerts when wax prices rise, so that I can reprice listings before selling at a loss.
▸As a PCB assembler, I want a visual BOM with live COGS, so that I know my exact margin before accepting a batch order. As an Etsy power seller, I want my margin floor enforced automatically, so that I never discover a pricing mistake at month-end.

Done When

✓BOM Builder: done when maker can add 20 components with quantities and prices without errors
✓Price Scraper: done when Cheerio correctly extracts price from 5 supported supplier URL patterns
✓Margin Alert: done when Resend email fires within 15 minutes of a price change breaching margin floor
✓Stripe Billing: done when Pro plan upgrade unlocks unlimited components immediately.

Is it worth building?

$19/month × 150 makers = $2,850 MRR at month 3. Realistic at 3% conversion from 5,000 Etsy seller outreach emails, which is achievable with an Etsy community presence.

Unit Economics

CAC: $10 via community outreach (1h founder time). LTV: $380 (20 months at $19/month). Payback: under 1 month. Gross margin: 91%.

Business Model

SaaS subscription

Monetization Path

Free tier: 1 product, 10 components. Pro $19/month: unlimited products and price alert rules.

Revenue Timeline

First dollar: week 3. $1k MRR: month 2. $5k MRR: month 7. $10k MRR: month 14.

Estimated Monthly Cost

Vercel: $20, Supabase: $25, Resend: $10, Stripe fees: ~$20. Total: ~$75/month at launch.

Profit Potential

Lifestyle business viable at $3k-$8k MRR. Strong niche with low churn once BOM is built.

Scalability

Add supplier API integrations for major distributors like Digi-Key and McMaster-Carr, team BOM sharing, and multi-currency support.

Success Metrics

Week 2: 20 beta makers with live BOMs. Month 2: 60 paid users. Month 3: less than 8% monthly churn.

Launch & Validation Plan

Post in 3 Etsy seller Facebook Groups asking if anyone tracks BOM costs, collect 20 email signups before building, offer free Pro for first 10 beta testers.

Customer Acquisition Strategy

First customer: DM 30 Etsy power sellers who sell physical goods with 50+ reviews, offering free Pro setup call. Ongoing: r/Etsy, r/smallbusiness, Etsy seller Facebook Groups, YouTube tutorials on maker COGS tracking.

What's the competition?

Competition Level

Low

What's the roadmap?

Feature Roadmap

V1 (launch): BOM builder, price scraper, margin alerts, Stripe billing. V2 (month 2-3): Digi-Key API integration, batch cost calculator, CSV import. V3 (month 4+): team BOM sharing, purchase order generator, multi-currency.

Milestone Plan

Phase 1 (Week 1-2): BOM builder and Supabase schema live, 10 beta makers entering real BOMs. Phase 2 (Week 3-4): scraper, margin alerts, and Stripe live, first real alert fired. Phase 3 (Month 2): 50 paid users, churn under 10%.

How do you build it?

Tech Stack

Next.js, Supabase, Cheerio for price scraping, Resend for alerts, Stripe — build with Lovable for UI, Cursor for scraping logic, v0 for BOM table components.

Suggested Frameworks

Cheerio, Supabase Realtime, Resend

Time to Ship

2 weeks

Required Skills

Next.js, Cheerio scraping, Supabase, Resend webhooks, basic margin math.

Resources

Cheerio docs, Supabase quickstart, Resend API docs, Etsy seller community for beta recruitment.

MVP Scope

bom-builder page, component table component, price-scraper API route (Cheerio), margin-calculator utility, alert-rules page, Supabase schema for products/components/prices/alerts, Resend alert email template, Stripe billing page.

Core User Journey

Architecture Pattern

Maker adds component with supplier URL -> Supabase stores BOM -> cron scrapes price via Cheerio -> new price saved -> margin recalculated -> if below floor threshold: Resend email plus Slack webhook fired -> dashboard reflects updated margin.

Data Model

User has many Products. Product has many Components. Component has many PriceSnapshots. Product has one MarginRule. MarginRule triggers Alerts.

Integration Points

Supabase for BOM and price history storage, Cheerio for price scraping, Resend for email alerts, Slack Webhooks for Slack alerts, Stripe for billing.

V1 Scope Boundaries

V1 excludes: inventory management, purchase order generation, multi-currency, team sharing, supplier API integrations.

Success Definition

A maker who found SupplyNest via a Facebook Group builds their full BOM, receives their first real price alert, and renews Pro after month one without any founder help.

Challenges

Distribution requires being inside Etsy seller and maker communities — ProductHunt will not find this audience. Need genuine presence in Facebook Groups like Etsy Seller Success and r/smallbusiness.

Avoid These Pitfalls

Do not attempt to auto-scrape every major supplier site in V1 — manual entry plus 5 supported sites is enough. Do not build inventory tracking before margin alerting is validated. First 10 paying customers will come from community not SEO — budget time accordingly.

Security Requirements

Supabase Auth with Google OAuth, RLS on all user product and component tables, rate limit 60 req/min per IP, sanitize all supplier URLs before scraping, GDPR data deletion endpoint for user BOM data.

Infrastructure Plan

Vercel for Next.js and cron jobs, Supabase for Postgres, Sentry for errors, GitHub Actions for CI, dev/staging/prod on Vercel. Total: ~$75/month.

Performance Targets

200 DAU at launch, 3,000 req/day. Scrape API under 3s per URL. Dashboard under 2s LCP. Cron runs every 6 hours, no real-time streaming needed.

Go-Live Checklist

☐Security audit complete
☐Payment flow tested end-to-end
☐Sentry live
☐Monitoring configured
☐Custom domain with SSL set up
☐Privacy policy and terms published
☐5 beta makers signed off
☐Rollback plan documented
☐Facebook Group and Reddit launch posts drafted.

First Run Experience

How to build it, step by step

1. Run npx create-next-app supplynest and install cheerio, supabase-js, resend, stripe. 2. Create Supabase schema for users, products, components, price_snapshots, margin_rules, alerts. 3. Build BOM builder page with editable component table using v0 data table component. 4. Create /api/scrape route using Cheerio to extract price from supplier URL. 5. Add margin calculator utility computing COGS and gross margin from component quantities and prices. 6. Build /api/cron route that loops all active components and fires scraper on schedule. 7. Add margin rule checker that compares new COGS to floor and queues alerts. 8. Integrate Resend to send margin alert email with component change summary. 9. Add Stripe Pro plan gating on component count. 10. Deploy to Vercel with cron job configured in vercel.json.

Generated

April 17, 2026

Model

claude-sonnet-4-6

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Disclaimer: Ideas on this site are AI-generated and may contain inaccuracies. Revenue estimates, market demand figures, and financial projections are illustrative assumptions only — not financial advice. Do your own research before making any business or investment decisions. Technology availability, pricing, and market conditions change rapidly; always verify details independently.