SOLUTION · CUSTOM SOFTWARE AND INTERNAL TOOLS
Custom inventory management system for your business
A custom inventory system records stock in, stock out and on-hand levels with the real rules of your operation — your units, your recipes, your warehouses — when generic software doesn't understand them. Before proposing a build, I check whether an off-the-shelf product will do, because it's often the cheapest option; when it isn't enough, I build what's missing.
What’s happening today
Spreadsheets work until several people edit them at once, someone deletes a formula or forgets to log a withdrawal. From then on, stock levels stop being reliable: the system says there are twenty cases and the warehouse has twelve. The result is over-ordering just in case, running out at the worst moment, or cash tied up in stock that doesn't move.
Generic inventory systems and ERPs solve much of the problem and, for standard buy-and-sell operations, they're usually the best option. The trouble starts with what doesn't fit their modules: ingredients that become finished goods according to a recipe, units that change along the way (bought by the case, stored by the pound, sold by the piece), lots with expiration dates, multiple warehouses with different rules, or transfers between locations.
When that happens, the clearest warning sign appears: the team uses the commercial system for invoicing but keeps the real inventory in Excel because the system "doesn't get how we work". You pay for the license and also enter everything twice, with twice the chances of error.
A custom system makes sense when those specifics are at the core of your operation. It can also be a complementary piece: the ERP or accounting system stays for invoicing and taxes, and the custom system handles only the part that doesn't fit, connected to everything else.
How I’d solve it
- 01
An honest assessment: buy or build?
We review your operation and the commercial options available. If an existing system covers your case, I'll recommend it even if that means I don't build anything. If not, we pinpoint exactly which part needs to be custom and what can stay in your current tools.
- 02
Model your real operation
We define products, ingredients, units and conversions, recipes or bills of materials, warehouses, lots and movement types as they happen today, including exceptions: shrink, returns, transfers between locations and adjustments after physical counts.
- 03
A first version with the essentials
Receiving, usage, stock per location and lookups from a phone. A usable first version within a few weeks, before adding advanced reports or integrations, so your team uses it with real data and we adjust from there.
- 04
Controls, history and alerts
User roles (who can record, adjust or only view), a history of every movement with who and when, and alerts when an item hits its reorder point or a lot is about to expire.
- 05
Migration, integrations and training
We import your current inventory from Excel, reviewing and cleaning the data before loading it. If needed, it connects to your POS or accounting system, and I leave documentation so your team can use it from day one.
Example: ingredients for a restaurant with two locations
- The manager logs ingredient deliveries from a phone as they arrive, by the case or by the pound.
- The system converts units and adds stock to each location's storeroom.
- At closing, sales from the POS deduct ingredients according to each dish's recipe.
- Transfers between locations are recorded with who, when and how much.
- When an ingredient drops below its minimum, the purchasing lead gets an alert.
- The weekly physical count is entered on a phone and the system shows variances and shrink.
Related work
Go deeper
Frequently asked questions
Why not use an existing inventory system?
If an existing one covers your operation, it's usually cheaper and faster, and I'll recommend it. Custom makes sense when your rules don't fit those tools — recipes, unit conversions, lots, production flows — or when you end up running inventory in Excel alongside the system you already pay for. There's also a hybrid option: the commercial system for invoicing and a custom one only for what doesn't fit.
Can the custom system handle invoicing and sales tax?
Invoicing and tax calculation are better left to specialized tools like QuickBooks, Xero or your existing accounting software, which keep up with tax rules. A custom system can integrate with them so inventory and invoicing stay in sync, but reinventing that part rarely makes sense.
Does it work on phones and with barcode scanners?
Yes. It's a responsive web app used from the browser on a phone, tablet or computer, with nothing to install. The phone's camera can read barcodes, and physical scanners can be used at the counter or in the warehouse.
What about the inventory I keep in Excel today?
It gets migrated. Before loading it, I review the data and show you the problem records — duplicate products, inconsistent units, negative stock — so they can be fixed. Starting with clean data is part of the project, not a detail.
What drives timeline and cost?
The number of modules (purchasing, recipes, production, locations, reports), integrations with other systems like POS or accounting, the amount and quality of data to migrate, and the number of user types. We start with a first version covering the essentials to reduce risk and upfront cost.
This solution is part of my custom software and internal tools service.
Want to talk it through?
If your situation sounds similar, tell me how you work today. I’ll tell you which part is worth automating or building first.