Utility rebilling calculator for small landlords

Micro-SaaS1 monthWeb

StackNext.jsSupabaseStripePostmark

Market read pendingWe are still researching this idea.
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The idea

A landlord with a four-unit building and one water meter does the split in a spreadsheet, emails tenants a number, and then argues about it. The dispute is never really about the amount; it is about the opacity. Meanwhile RUBS billing services exist but charge per unit with contracts, built for 200-unit complexes, absurd at this scale.

The dispute-killer is showing the full math on every bill: total, method, your factor, your share, provider bill attached. A tenant can disagree with a policy, but not with arithmetic they can check. Add payment links and reminders and the landlord’s monthly chore drops to entering one number.

Who pays

Landlords with 2-20 units pay 15 USD/month, self-serve, no contract, which is precisely what the per-unit RUBS incumbents refuse to offer. It replaces an hour of spreadsheet work and at least one tense email thread per month. Distribution: BiggerPockets forums, small-landlord subreddits and Facebook groups, and SEO on how to split utilities between tenants, a high-intent evergreen query.

MVP scope

  • Properties and units with square footage, occupants, and tenant contacts
  • Bill entry with even, square-footage, occupant, and custom-percentage allocation
  • Per-tenant PDF bills showing the complete calculation, sent via Postmark
  • Stripe payment links with day-7 and day-14 reminders and status tracking
  • Per-state RUBS restriction notes in plain language
  • Skip for v1: submeter hardware integrations, lease management, rent collection, tenant portal accounts, non-US compliance
// Build prompt — paste into Cursor / Claude Code / Lovable / Bolt
Build SplitMeter, a web app that lets small landlords rebill shared-meter utilities to tenants with the maths shown.

Stack: Next.js (App Router), Supabase (Postgres + auth + storage), Stripe for tenant payments, Postmark for email delivery.

Core flow: the landlord sets up properties and units, each unit with square footage, occupant count, and tenant name and email. Each billing cycle, they enter a utility bill (type, provider, period, total, optional bill PDF upload) and pick an allocation method per bill: even split, by square footage, by occupant count, or a custom percentage table saved per property. The app generates a PDF bill per tenant that shows the complete calculation: total bill, method, the tenant's factor, and their share, with the landlord's uploaded provider bill attachable as backup. Bills go out via Postmark with a Stripe payment link; payment status tracks per tenant per cycle with automatic day-7 and day-14 reminder emails.

Pages: magic-link login, properties and units setup, new-bill wizard with a live allocation preview across units before sending, billing-cycle history with payment statuses, tenant ledger per unit, a compliance-notes page with plain-language per-US-state summaries of where RUBS billing is restricted or requires lease language, settings, billing.

Implementation details: round shares using largest-remainder so the split always sums exactly to the bill total. Store every sent bill immutably; corrections issue a superseding bill.

Pricing: 15 USD/month up to 20 units via Stripe Checkout, 30-day trial.

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