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ERP software development. One system, your process.
ERP software development builds the system that ties stock, orders, purchasing, production and finance together, so each number is entered once and seen everywhere. yop develops custom ERP software in Tallinn for growing companies, one module at a time, connected to the accounting, e-invoicing and marketplace tools you already use.
Custom ERP
Custom ERP or off-the-shelf ERP?
Start small
The module that removes the worst spreadsheet comes first. The next one is priced once the first is in daily use.
Off-the-shelf ERP such as SAP Business One, Microsoft Dynamics 365, NetSuite or Odoo works well when your processes match the way the software expects a business to run. When they don’t, companies pay for modules they never open and run the real work in spreadsheets beside the ERP.
Custom ERP software development starts from your process instead. We build the modules you need, in the order that pays back first, and connect them to the tools that already work, such as your accounting software. For small and mid-sized companies that often means a lean system of three or four modules rather than a full suite.
- Inventory and warehouse. Stock levels, locations, transfers and counts, with barcodes where they help.
- Orders and purchasing. Quotes, sales orders, purchase orders and supplier prices in one flow.
- Production. Bills of materials, work orders and the status of each job on the floor.
- Finance links. Invoices, payments and costs flow into your accounting software, so nobody types them twice.
Modules we build
The parts of an ERP we build most.
Stock and warehouse
Live stock per location, minimum levels, transfers and counts, on a desktop and on a phone in the warehouse.
Sales and orders
Quotes that become orders, delivery notes and invoices, with customer prices and discounts kept in one place.
Purchasing
Purchase requests, approvals, supplier orders and goods received, matched against supplier invoices.
Production planning
Bills of materials, work orders, capacity and job status, so the office sees what the floor is doing.
Reporting
Stock value, margins, late orders and cash on dashboards built from the same data, not from exported sheets.
Integrations
E-invoicing, accounting, cargo, marketplaces and banks connected through their APIs.
Compare
Custom ERP or a ready-made suite?
| Custom ERP compared with off-the-shelf ERP | Custom ERPOur pick | Off-the-shelf ERP |
|---|---|---|
| Fit with your process | Built around it | You adapt to it |
| Licences | None | Per user, every year |
| How it starts | One module, then the next | Usually the whole suite |
| Integrations | Any system with an API | What the vendor supports |
| Upfront cost | Higher per module | Lower to start |
| Ownership | You own the code and data | You rent the software |
How it runs
Five steps to go-live.
Map
We follow an order, a purchase and a production job from start to finish and note every spreadsheet and copy-paste.
Plan
Modules ranked by what they save, a data map, and a fixed price for the first module.
Build
Built in short rounds on a test copy loaded with your real data, and checked by the staff who will use it daily.
Move the data
Products, customers, stock and open orders migrated, checked and reconciled before go-live.
Go live
Training, a parallel week beside the old way, then support while the next module is planned.
Cost and timing
How much does custom ERP development cost?
Custom ERP cost depends on the number of modules, users and integrations, and on how messy the data is that has to move. Building one module at a time keeps each step small: yop gives a fixed price for the first module after the mapping workshop, and prices the next once the first is in daily use.
In Türkiye, our software brand pirdir offers ready-made modules for stock, orders, field service and finance that we adapt to each company, which shortens the build for small businesses there.
Your ERP
Start with the worst spreadsheet.
Point us to the process that costs your team the most hours now. Expect our answer two working days later: how we would map it.
Questions
Asked about ERP.
What does custom ERP development mean?
Custom ERP development means writing enterprise resource planning software that follows how one company handles stock, orders, purchasing, production and finance, rather than bending the company to fit an off-the-shelf suite.
What does custom ERP software cost?
The modules, the number of users, the integrations and the data migration set the price. yop prices one module at a time, as a fixed price agreed after a mapping workshop.
When could the first part of a custom ERP system be running?
The first module typically goes live a few months in. A full system grows module by module, with each module in use before the next one starts.
Can you build just one ERP module?
Yes, and we recommend it. The first module removes the most costly manual work; the rest follow once it has proved itself.
Can a custom ERP connect to our accounting software?
Yes. yop connects ERP modules to accounting, e-invoicing, banks, cargo companies and marketplaces through their APIs, so data is entered once.
How does data get out of our old system?
Field by field: we map it, remove duplicates, move products, customers, stock and open orders into a test copy, and check the totals with you before launch.
Who owns the ERP code and data?
Your company does. The code repository, database and hosting are opened in your name from day one, and yop works in them as a guest.
Floor 01 · Build
More on the Build floor
Software development services from yop in Tallinn: custom software, SaaS, CRM, MVP and network marketing systems, with the code and data in your name.
Software built around how your company already works.
Subscription products with accounts, plans and billing.
The smallest real product that paying users can try.
iOS and Android apps your team and customers keep using.
A CRM built around how your team sells and serves.
Orders, invoices and requests, open to customers around the clock.
The numbers and screens your team opens every morning.
Back office, genealogy and commissions, built for your plan.







