What is the difference between an ERP and a CRM?

The ERP covers what happens inside the company: stock, purchasing, invoicing, accounting. The CRM covers the relationship with customers before and after the sale: contacts, opportunities, follow-up. Many companies use both, connected to each other.

How much does an ERP cost?

A standard ERP is paid in licences, per user or per month, plus the implementation, which often costs more than the licences. Custom software is paid in hours or days of development. We work in Paraguay at USD 70 an hour or USD 560 a day and estimate the work in writing before we start.

Isn't an Excel spreadsheet enough?

For a small company, for a while, yes. It stops being enough when several people enter the same thing in different spreadsheets, when nobody knows the real stock without asking, or when a formula error reaches a customer.

Do we have to replace the whole current system?

Almost never. Accounting, payroll and stock are solved problems and standard products do them well. What is usually worth building is the part specific to how your company makes money, connected to the ERP that already works.

What Is an ERP, and When Does Custom Software Make Sense?

An ERP is the management system where a company keeps its accounting, stock, purchasing, sales and invoicing in one place. For most of that, a standard product is enough; custom software only makes sense for the part that is specific to your business.

Updated: 27 October 2026 · By Andreas Walther, founder of Contrast Concepts

What an ERP does

A piece of data is entered once and everyone sees it.

Sales and invoicing

Quotes, orders and invoices. In Paraguay, with electronic invoicing under the SET's SIFEN system.

Purchasing and stock

What there is, where it is, what needs ordering and from whom. The real stock, without having to ask.

Accounting

Every sale and every purchase is posted to the accounts automatically, instead of being entered twice.

Reports

Sales, margins and outstanding payments in view, without building a spreadsheet by hand every month.

Standard ERP or custom software?

Almost always, both.

Standard, for what is the same everywhere

Accounting, payroll, stock and invoicing work much the same in every company. There, a standard product is cheaper, better tested and maintained by someone else. Rebuilding it rarely makes sense.

Custom, for what is only yours

The way you quote, produce, ship or serve your customers is the reason they buy from you. When the ERP forces you to change that, or to keep it alive in side spreadsheets, that part is worth building and connecting to the ERP.

Signs the spreadsheet is no longer enough

Several people enter the same data in different spreadsheets.
To know the real stock, you have to ask someone.
Closing the month depends on one person and their formulas.
A spreadsheet error has already reached a customer or an invoice.
Your current system cannot do something key, so it gets done "on the side".

What to look for in an ERP in Paraguay

Electronic invoicing. It should issue documents under SIFEN without expensive add-ons.

Local support. Someone who answers in your time zone and your language when something breaks on a Friday afternoon.

Your data, exportable. You should be able to take all your information out in an open format if you ever switch systems.

Connections. It should have an API, so you can connect your shop, your CRM, WhatsApp or whatever you build to measure.

Frequently asked questions about ERP

What does ERP stand for?: ERP stands for Enterprise Resource Planning. In practice it is the management system where a company keeps its accounting, stock, purchasing, sales and invoicing in one place.
What is the difference between an ERP and a CRM?: The ERP covers what happens inside the company: stock, purchasing, invoicing, accounting. The CRM covers the relationship with customers before and after the sale: contacts, opportunities, follow-up. Many companies use both, connected to each other.
How much does an ERP cost?: A standard ERP is paid in licences, per user or per month, plus the implementation, which often costs more than the licences. Custom software is paid in hours or days of development. We work in Paraguay at USD 70 an hour or USD 560 a day and estimate the work in writing before we start.
Isn't an Excel spreadsheet enough?: For a small company, for a while, yes. It stops being enough when several people enter the same thing in different spreadsheets, when nobody knows the real stock without asking, or when a formula error reaches a customer.
Do we have to replace the whole current system?: Almost never. Accounting, payroll and stock are solved problems and standard products do them well. What is usually worth building is the part specific to how your company makes money, connected to the ERP that already works.

Custom software with us

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