ecomrestack

battles / ERP & Inventory

Erply vs Inventory Planner

Erply ($450/mo/mo, vibe code 3/10) vs Inventory Planner ($450/mo/mo, vibe code 3/10). Inventory Planner is the easier one to rebuild yourself — here is what you lose either way.

Erply
KEEP

ERP & Inventory

$450/mo/mo

Vibe code3/10
Moat4/10
MVP
2 months
Full replacement
12-24 months, due to hardware device drivers, offline sync queues, and multi-location accounting edge cases.
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Inventory Planner
KEEP

ERP & Inventory

$450/mo/mo

Vibe code3/10
Moat3/10
MVP
2 weeks
Full replacement
6-9 months, due to complex forecasting algorithms, high-density matrix UI data grids, and edge cases like stockout masking.

easier to rebuild

get the build prompt →

price gap / year

usage-based

running both / year

$10,800/mo

our call

Start with Inventory Planner — highest vibe code, weakest moat.

Erply

Erply controls the operational plumbing of retail: physical receipt printers, payment terminal bridges, offline sync queues, and matrix item variants. Building a basic web inventory list with AI is easy, but maintaining network-resilient register hardware integrations and complex FIFO inventory ledgers across physical locations is not feasible with prompt-generated software.

you can rebuild

  • Product catalog management and matrix variant definitions
  • Customer records and simple loyalty points tracking
  • Basic manual stock adjustments and intra-warehouse transfer orders
  • Web-based register UI for touch-screen product selection
  • Standard sales dashboard reporting and inventory valuation metrics

what you lose

  • Native local hardware wrappers for receipt printers, cash drawers, and barcode scanners
  • Offline-first POS register state engine using local browser storage and sync queues
  • EMV credit card reader direct integrations (Ingenico, Verifone, PAX)
  • Fiscal memory cash register compliance modules for strict European tax jurisdictions
  • Automated purchase order generation based on historic reorder points

real moats

  • Hardware integration layer abstracting physical payment terminals and peripherals
  • Operational switching costs associated with retraining retail floor staff across multiple locations
  • Localized retail fiscal tax compliance and audit-trail engines

open source escape hatches

Inventory Planner

While simple reorder point math can be scripted in a afternoon, replacing Inventory Planner's full UX is a massive engineering effort. The app relies on complex statistical forecasting, stockout masking, multi-location transfers, and an inline-editable matrix grid optimized for high-volume SKU management.

you can rebuild

  • Basic moving-average and order velocity calculations per SKU
  • Simple reorder point triggers based on static lead times and safety stock
  • Automated PDF or CSV Purchase Order draft creation
  • Low stock alerts delivered via email or Slack
  • Basic historical sales data import via Shopify Webhooks/APIs

what you lose

  • Stockout days auto-adjustment (removing zero-sales days caused by stockouts from velocity math)
  • Advanced statistical forecasting models (Holt-Winters, linear regression with seasonal indicators)
  • Bill of Materials (BOM) assembly stock explosion for raw component planning
  • High-density, spreadsheet-like inline editing UX optimized for bulk adjustments
  • Native multi-warehouse transfer recommendations and multi-location balancing

real moats

  • Deep data grid UI engineering with inline cell overrides and instant recalculated projections
  • Battle-tested forecasting algorithms refined across edge cases like stockouts, promotions, and supply chain delays
  • Pre-built integrations with major ERPs, WMSs, purchase order systems, and sales channels

open source escape hatches

Questions people ask

Which is easier to rebuild with AI, Erply or Inventory Planner?

Inventory Planner. It scores 3/10 on vibe code with a moat of 3/10, so an AI-assisted MVP takes about 2 weeks and a full replacement about 6-9 months, due to complex forecasting algorithms, high-density matrix UI data grids, and edge cases like stockout masking..

Which one costs less, Erply or Inventory Planner?

Erply at $450/mo/mo for a typical mid-market store. The gap between the two is about usage-based a year.

What do I lose if I replace Erply?

Native local hardware wrappers for receipt printers, cash drawers, and barcode scanners Offline-first POS register state engine using local browser storage and sync queues EMV credit card reader direct integrations (Ingenico, Verifone, PAX)

What do I lose if I replace Inventory Planner?

Stockout days auto-adjustment (removing zero-sales days caused by stockouts from velocity math) Advanced statistical forecasting models (Holt-Winters, linear regression with seasonal indicators) Bill of Materials (BOM) assembly stock explosion for raw component planning

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