An SME manufacturer that wants to get out of Excel to manage its production has three roads ahead: off-the-shelf MRP software, the manufacturing module of its ERP, or custom MRP software built around its own processes. Each has its advocates, and they are rarely neutral.
We have delivered custom developments, and we also implement an off-the-shelf ERP. This article sets out an honest decision grid: what each option costs, what it imposes, what it makes you dependent on, and in which cases custom development is really justified.
Three ways to equip an SME with production management software
The scope of production management software is always the same core: items, bills of materials, routings, manufacturing orders, shop floor tracking. What changes is how you get it.
- Off-the-shelf MRP software. A specialist software package, sold under licence or by subscription, configured by an integrator. It covers a broad scope.
- The ERP module. If the company already has an ERP, or is choosing one, its manufacturing module handles manufacturing orders, consumption and stock with no interface to build. It is the most integrated option, and often the least detailed for planning.
- Custom MRP software. An application developed for the company, from its own rules. It does exactly what was asked for, no more, no less, and it lives as long as someone knows how to maintain it.
What each option really costs
On the large packages on the market, we have seen integrators charge up to €1,100 a day for installation and configuration, maintenance contracts of around €2,000 a month for updates and support, and licences of €50,000 to €100,000 a year, servers not included. These amounts concern the large packages, not production software designed for SMEs, but they are a reminder: the “licence” line is only one line among others.
| Criterion | Off-the-shelf software | ERP module | Custom MRP software |
|---|---|---|---|
| Initial cost | Licence or subscription, plus integration days | Often included, configuration to pay for | Development days, no licence |
| Recurring costs | Licences, maintenance, version upgrades | Included in the ERP subscription | Limited, negotiated maintenance, hosting |
| Time to go-live | Depends on the configuration and the integrator | Tied to the ERP project | Depends on scope; a first release can ship quickly |
| Fit with your processes | Good on standard processes, limited on specific ones | That of the ERP | Complete, by design |
| Dependency | On the vendor and the integrator | On the ERP vendor | On the provider who developed it, and on its documentation |
| Changes and new features | At the vendor's pace | At the ERP's pace | At the company's pace |
The “structuring effect”: a benefit or a sales pitch?
Vendors often present the structuring effect as a benefit: by adopting the software, the company adopts good practice. Sometimes that is true. An SME with no clean routings or bills of materials gains from a tool that forces it to create them, and accurate item master data is the precondition for any planning.
But the argument is also used to dress up something else: the software cannot do what you do, so you will do it differently. The warning sign is when users adapt their work so that the tool functions, instead of the tool helping them day to day. A scheduler re-keying into a separate file because the tool's screen does not show what they need is a structuring effect that has failed. The question to ask is simple: is what the tool imposes a recognised good business practice, or a limitation of the tool?
When custom MRP software for an SME is justified
Custom development is justified in four situations that we meet regularly.
- The process is a differentiator. The way you schedule, trace or manage batches is part of your competitive advantage. Standardising it means giving it up.
- The standard has been tried. The company has evaluated two or three off-the-shelf tools and comes up against the same specific points each time, identified in writing.
- The ERP must remain the master. The company keeps its ERP for stock, manufacturing orders and purchasing, and only lacks a connected planning or shop floor tracking layer.
- The number of users makes licences disproportionate. For an industrial client, we developed a production management web application used by more than 200 people, which we host on AWS. At that scale, a per-user licence would have weighed heavily for functions the company did not need.
Conversely, custom development is not justified when the need is standard (managing manufacturing orders, stock and purchasing), when the team is very small, or when nobody in-house can lead the project. In those cases, simple MRP software or the ERP module will do better, faster, and without making the company dependent on a one-off development.
Decision grid in six questions
| Decision question | If yes | If no |
|---|---|---|
| Do you already have an ERP that manages items, stock and manufacturing orders? | ERP module, or a tool connected to the ERP | Off-the-shelf MRP software or a full ERP |
| Are your planning rules written down and specific? | Custom, or a tool with programmable columns | Standard solution |
| Has an off-the-shelf tool been tested on your real cases? | Decide on the gaps observed | Test before developing |
| Can someone in-house lead the project? | All options remain open | Standard, with an integrator |
| Are there more than a few dozen users? | Compare licences and development | Licences are affordable |
| Do you accept depending on a single provider? | Custom is possible, with code and documentation handed over | Standard solution |
The risks of custom development to face squarely
- Dependency on the provider. Require the source code, the documentation, access to the hosting and a handover procedure.
- Scope creep. Custom production software can do anything, so it gets asked to do everything. Setting a useful first release, then iterating, is better than a never-ending project.
- Hosting and security. Backups, server updates, access management: these are recurring costs, even without a licence.
AI has made custom development faster and more accessible, and a provider who combines business expertise, project management and technical skills now delivers in a shorter time. But it replaces neither gathering the requirements nor testing on the shop floor's real cases.
What we see in the field on build versus buy
The choice is rarely as clear-cut as the brochures suggest. The SMEs that do best combine two layers: an ERP or standard software for everything transactional (items, stock, manufacturing orders, purchasing), and a specific layer, or a tool whose rules can be programmed, for planning and shop floor tracking, where their know-how makes the difference. We also see custom projects launched to avoid a structuring effect, when the real problem was item master data that had never been cleaned up: no development fixes wrong bills of materials.
Finally, the provider's business experience matters as much as their technical skills. Our background as planning and logistics managers lets us understand the need from the first scoping workshop, and saves weeks of back-and-forth. End-to-end support, from gathering requirements to training, counts for more than the choice of programming language.
Conclusion: custom MRP is neither folly nor a given
Custom development is neither folly nor an obvious choice. It is justified when the process is a differentiator, when the standard has been tested and has failed on specific points, and when the company can lead the project. In other cases, simple MRP software or the ERP module is enough, provided you do not mistake a limitation of the tool for a structuring effect. For the technical side of the choice, we have described what web-based production software changes for an SME and what needs to be scoped before development starts.
At Planitools, we have chosen a third way for SMEs: standard software, Planitrack for shop floor tracking and Planiprod for planning, whose calculation rules can be programmed column by column, connected to any ERP, and an Odoo integration for those who do not yet have an ERP. Our page simple MRP software for SMEs explains this approach; you can also request a demo.