Micro-app or ERP module: how to decide where a shop-floor task belongs

Every factory eventually has a task that the ERP almost covers. Goods receipt works, but the incoming inspection needs photos. Work orders exist, but the operator at a test jig needs one screen with one button. So: bend the ERP, or build a small app next to it? The answer depends on the task.

We do not start from the tool. We start from the task, and ask five questions.

Who does it, and where?

An ERP screen is built for a person at a desk with a keyboard. A task done standing at a jig, wearing gloves, with a barcode scanner in one hand, wants a different screen. If the operator handles a unit every 30 to 60 seconds, a single-purpose app on a tablet usually wins. An accounts clerk is a different case. The ERP wins.

Does it need hardware?

Reading a serial number from a USB barcode scanner is easy in either. Talking to a device under test over UART, Modbus RTU or Bluetooth Low Energy is not. ERP modules rarely open serial ports or run a test sequence with timeouts. A test station, a flashing and provisioning step or a label printer driven by ZPL or TSPL belongs in a small app that reports its result to the ERP afterwards.

How often does the process change?

Customising an ERP module means a change request, a test cycle and often a release window. A downtime reason list that changes monthly does not fit that rhythm. A process that has been stable for years and touches stock, costing and accounts does.

Who owns the numbers?

This decides most cases. Stock, bills of materials, costing, purchase orders and invoices should have one owner, and that owner is the ERP. A micro-app should read those records and write back events: unit tested, batch passed, quantity scrapped. It should not keep its own copy of stock.

What happens if it is down?

If production stops when the app is unavailable, it needs a plain fallback and a plan for syncing later. If a missing ERP screen only delays an entry, the ERP is acceptable.

A rule of thumb

We keep the system of record in the ERP and put the system of work next to the operator. The micro-app captures an event once, at the place it happens, and pushes it through the ERP’s API. Odoo, for example, exposes its models over JSON-RPC and XML-RPC, so a test result can become a quality check record without anyone retyping it.

Where this does not apply

If the ERP already has a module for the task and your team is happy with it, build nothing. A micro-app is another thing to maintain, with its own logins, backups and updates. Two apps that both hold the same quantity will disagree sooner or later, so if you cannot say which one wins, stop and settle that first.

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If you have a shop-floor task that sits awkwardly between a spreadsheet and your ERP, we build micro-apps for electronics and manufacturing and can look at it with you, so book a discovery call.