Visual product configuration
The user picks the shape from a graphical selector — any polygon from 3 to 12 sides. The app draws it automatically and asks for the dimensions: every side, plus the two end hooks. No formulas, just measurements.
Case study2024
Meta Calculator — order management and weight calculation
A custom web app for a rebar stirrup manufacturer
The goods sell by the kilogram, and the weight was worked out by hand — on paper or in Excel — for every product in every order. One misplaced decimal meant a wrong quote. We built the app where the shape is configured visually, the weight computes itself — in the interface and once more on the server — and the order tracks its own status through to completion.
StackNext.jsReactTypeScriptPostgreSQLPrisma
- Client
- Rebar stirrup manufacturer · construction
- Project type
- Custom web application for order management
- Our role
- Architecture, development, delivery
- Status
- Delivered and in daily use
The context
The price depends on the weight. The weight, on a manual sum.
The client manufactures rebar stirrups — steel bars bent into various geometric shapes, ordered by construction firms. Every order means a calculation: given the shape, the dimensions of each side and the diameter of the bar, you have to work out the total weight. The goods sell by the kilogram, so the price depends on it directly.
That calculation was done by hand, on paper or in Excel: add up the length of every side, multiply by the weight-per-metre of that diameter, then by the quantity. For every product, in every order.
- Manual weight calculations, product by product, order by order
- One misplaced decimal = a wrong quote, and money lost
- Orders and customers scattered across files and notebooks
- No overview of what was in production and what was done
“
They needed one place where the product gets configured, the weight comes out right every time, and the order stops getting lost between a spreadsheet and a notebook.
What we built
The whole business, in one place.
A web app where the person on the shop floor never has to know a formula — they just enter the measurements already on the technical drawing. The app does the rest: draws the shape, computes the weight, ties the product to an order and the order to a customer.
Shape + dimensions
Automatic calculation
Order · PDF
Pick the polygon, fill in the sides and the bar diameter. The weight appears instantly, and the order moves on as a document, ready to send.
Delivered capabilities
Automatic weight calculation
As the dimensions and bar diameter go in, the app instantly computes the weight per piece and the total for the ordered quantity. The same calculation is redone on the server on save — so what gets stored is always right, whatever happened in the browser.
Full order management
Every order belongs to a customer — contact details, company, address, notes — and holds any number of products. Orders carry a status: New / In production / Completed / Cancelled, so it's clear at a glance what's in progress and what's done.
PDF export
The order exports as a document, ready to send to the customer or take onto the shop floor.
Standalone calculator
For the times someone just wants a quick weight, without recording an order at all.
Accounts and roles
Email and password sign-in. Administrators work with orders, customers, the calculator and exports; a higher role can create accounts and manage users. Every page and every data route is guarded on the server — nobody bypasses the rules by poking at the browser.
Details that matter
Where calculation apps usually go wrong.
01
The formula lives in exactly one place
When the calculation rule is written in ten places — once in the form, once on save, once in the export — sooner or later they stop agreeing. And then nobody knows which number is the real one.
Details that matter
The weight rule (d² / 162, the industry-standard formula) is defined once, in a dedicated module, and used identically in the interface and on the server. Here it simply can't drift.
02
Validation on the server, not just in the form
A browser form can be bypassed, and a bad value that lands in an order turns straight into a bad invoice.
Details that matter
Dimensions and quantities are validated and recomputed on save, server-side. The interface helps the user; the server guarantees the data.
03
Built for people on the shop floor
Internal tools usually end up as a dry form — and then people quietly go back to Excel.
Details that matter
A clean interface with light and dark mode, loading states and visual feedback on every action. Built for people who work in production, not for programmers.
04
The data no longer lives on one PC
An Excel file on someone's workstation disappears along with that workstation — and takes the entire order history with it.
Details that matter
Data sits in a cloud-hosted PostgreSQL database, with backups. Reachable from anywhere, lost nowhere.
The outcome
From paper and Excel to a single flow.
The company moved from manual sums and orders kept in scattered files to an app where the product is configured visually, the weight computes itself correctly, and the order exports to PDF and tracks its status through to completion.
Calculation errors — which used to translate directly into lost money or wrong deliveries — are out of the process.
3–12
Sides — any polygon, configured visually
2×
The weight is computed in the UI and again on the server
1
Place where the formula lives, used identically everywhere
PDF
Order exported, ready to send or take to production
Still running a critical calculation in a spreadsheet?
We move it into an app where the formula is written once and the result is guaranteed on the server — not in the form.