Published on October 25, 2026 · The mitza.es team
“Do I need an ERP, a CRM or both?” is one of the questions we hear most often when a small business starts to feel that its spreadsheets can't take any more. The short answer is that it depends on what is holding you back: if you're losing customers or opportunities, start with a CRM; if you're losing time and money on orders, stock or invoices, think about an ERP. The long answer has more nuance, and also a third route that almost nobody tells you about: custom software. Let's take it step by step.
ERP and CRM: what each one does (and why they don't compete)
An ERP (enterprise resource planning) handles internal management: invoicing and accounting, purchasing, inventory, production, logistics and, sometimes, human resources. A CRM (customer relationship management) handles what happens before and after a sale: contacts, opportunities, sales follow-up, quotes, customer service and, in many cases, email marketing.
They don't compete, they complement each other. A practical rule sums up the difference well: the ERP organizes operations and the CRM organizes revenue. That's why many companies start with one and add the other when the business calls for it, and what matters is that the two talk to each other so you don't type the same data twice.
What does your business need: ERP, CRM or both?
These are the most common signs, so you can identify your case:
- You need a CRM if contacts and quotes live in emails, notebooks or loose spreadsheets, if nobody knows where each opportunity stands or if a customer is left without a reply because “the email got lost”.
- You need an ERP if invoices, orders and stock are in different places, if inventory never adds up, if you close the month by copying figures from one program to another or if your accountant asks you to sort out the information every quarter.
- You need both when you sell on a recurring basis, have a catalogue, orders or projects and also manage a customer base you want to grow. In that case, what matters most is how they integrate.
- You may not need either yet if you invoice little, have few customers and a simple invoicing program covers you. Bringing in a full ERP too early is one of the most expensive ways to complicate your life.
The three routes: cloud software, open source or custom
1. Software as a service (in the cloud)
This is the most common option: you pay a monthly subscription per user or per plan (Holded, Sage, Zoho, HubSpot and similar) and use it from the browser. The upsides: you start in days, you don't maintain servers and the provider handles updates, including regulatory ones. The downsides: you pay for every user for as long as the contract lasts, you adapt to the way the tool works and your data lives on its platform.
2. Open source
Odoo, for example, offers a free, open-source Community edition and a paid Enterprise edition priced per user. With the free edition you don't pay for a licence, but you do pay for hosting, implementation and support, and some features you might take for granted (such as part of the bank synchronization or multi-company support) are only in the paid one. It's a good option if you have someone to set it up and maintain it.
3. Custom
Software built for the way you work, with the features you use and none of the ones you don't. It's the most expensive option up front and the most flexible in the medium term. It fits when your process differs from the standard or when the software has to be tightly tied to your website or your online shop. We look at it in more detail below.
Free CRM: what it includes and where the limit is
There are serious free CRMs. HubSpot has a free plan that doesn't expire, and Zoho CRM offers a free edition aimed at very small teams. To start organizing contacts and opportunities, they're a good no-cost trial. But it helps to know how they're funded:
- User and feature limits. Comparisons don't fully agree on the figures (and they change over time), so check the official website for how many users and contacts each plan allows today.
- The price jump. Typically the first paid plan kicks in when you need automations, reports, custom fields or want to remove the provider's branding, and it's bought for the whole team. Work out what it would cost with your headcount a year from now, not today's.
- Your data. Before loading your customer base, check that you can export all of it in an open format (CSV). It's your insurance if you ever switch tools.
What it really costs (and why the licence is the smallest part)
Comparing only the monthly price per user is the most common mistake. The real cost of an ERP or a CRM has several layers:
- Licence or subscription: per user, per module or per plan.
- Implementation and setup: adapting the program to your processes, your invoice series, your rates and your permissions.
- Data migration: cleaning up and moving customers, products, history and balances. It almost always takes longer than planned.
- Training and rollout: if your team doesn't use it, whatever you paid is worth nothing.
- Integrations: with your website or shop, your payment gateway, your POS, your bank or your accountant.
- Maintenance and regulatory changes: especially in invoicing (see below).
An Odoo cost guide (Softabase) estimates that the licence accounts for only 15% to 25% of the total spend over three years; the rest goes on implementation, customizations and support. It's a reference for one specific ERP, but the order of magnitude holds for any of them: always ask for the full quote, not just the licence price. And if you'd like to know how we approach quotes, you can see our pricing page.
When building custom pays off
Custom software isn't for everyone, and sometimes the right answer is “buy an off-the-shelf program”. It's worth considering when several of these circumstances apply:
- Your process is unique and an off-the-shelf program forces you to work against the grain or to keep spreadsheets running in parallel.
- The system has to be integrated with your website or online shop: orders, stock, customers and invoices flowing without copying data by hand.
- You'll have many users (for example, employees, sales reps or customers with access) and paying for every licence would make the cost balloon over the years.
- You handle sensitive information or need to control where the data lives and who can access it.
- What you need is small, but very specific: a customer portal, a booking system, a quoting tool. Building it custom can cost less than adapting a giant ERP.
And there's a middle option that is often the best: an off-the-shelf program for the standard stuff (accounting, invoicing) and custom development only for what sets you apart, joined together by integrations and automation. You pay to develop only what truly doesn't exist.
Checklist before you decide
- What specific problem do I want to solve, and how will I measure that it's solved?
- How many people will use it today and in two years?
- Which processes are standard and which are unique to my business?
- Does it connect with my website or shop, my bank, my payment gateway and my accountant?
- Can I export all my data, in full, if I want to leave?
- Where is the data stored and how does the provider comply with the GDPR?
- Is support available in my language and during my working hours?
- How much will it cost me in total over three years, with implementation and training included?
- Does it comply (or will it comply) with VeriFactu and e-invoicing, and at what price?
- Who takes care of backups? If it's the provider, what do they guarantee?
VeriFactu and e-invoicing: the requirement you can't skip
If the program is going to issue your invoices, it has to meet the requirements for invoicing computer systems. Having the provider handle regulatory updates is a huge advantage of cloud software, as long as it's included in the price and isn't a separately paid module. Ask for it in writing. The dates matter: business-to-business e-invoicing will become mandatory on October 6, 2027 for companies invoicing more than €8 million and on October 6, 2028 for everyone else, under Order HAC/1028/2026, and VeriFactu still has its timetable under review. You'll find the details in our guide on how to choose invoicing software and in the digital compliance calendar.
The mistakes we see most often
- Buying the most complete ERP “just in case”. The more features, the longer the implementation and the more likely nobody will use it.
- Starting without cleaning the data. Migrating duplicates and errors into a new system only makes them harder to spot.
- Not involving the people who will use it. If the team has no say in the choice, they'll dodge it with their usual spreadsheet.
- Forgetting about backups. Your customer base and your invoicing are the most valuable things you have; see our guide on 3-2-1 backups.
- Getting locked in to a provider. Check contracts, minimum terms and, above all, how you get your data back if you leave.
How we approach it at Mitza
We don't sell an ERP or a CRM: we help you decide what's needed and, when it makes sense, we build it. If what you need is small and very specific (a portal for your customers, a booking system, a quoting tool or the connection between your website and your invoicing program), we usually propose it as custom web development, with a fixed scope and no per-user licences. If what you're after is a website or shop that integrates with your systems, we handle it within our web development service. And if an off-the-shelf program covers you, we'll tell you so.