Open-source alternatives to NetSuite and Sage

Let's start with the honest bit. This is the biggest move on this whole site, and for lots of businesses it's the wrong one. NetSuite and Sage are serious systems that do a serious job, and I wouldn't tell anyone to rip them out to save money.

But it's a fair thing to ask if you're looking at them for the first time and the quote made you wince. Neither publishes a price. NetSuite is an annual licence built from a core platform, optional modules and a number of users, with a one-time implementation fee on top. Sage says Intacct pricing is tailored to your users, modules and requirements.

The approach I'd look at here is different from a straight swap. Keep your accounting in Xero or QuickBooks, which are good at it and which your accountant already knows, and use an open-source system for what they don't do: stock, orders and operations.

ERPNext

ERPNext comes from Frappe and it's the fully open option. Its site says features aren't locked behind paywalls, and that's the main reason it's my preference. The licence is GPL-3.0 and there's no separate paid edition.

• Stock management: tracking, replenishment and shipments.
• Sales and purchasing: quotes, orders, customers and suppliers.
• Manufacturing: production, material use, capacity planning and subcontracting.
• Assets, projects and point of sale.
• Accounting, if you do want it all in one place.
• HR and payroll, through the separate Frappe HR app.
• A no-code builder for custom forms, reports and workflows.

Running it isn't a small job. Version 16 needs MariaDB 11.8, Node 24 and Redis on Debian 13 or Ubuntu 24.04 or later. The Docker quick start is labelled a disposable demo, so production needs the fuller setup. I couldn't find an official memory figure, so size the server with whoever's setting it up.

If you don't want to run it yourself, Frappe Cloud hosts it, and you pay for the hosting rather than per user. Frappe's own site says self-implementation is complex and recommends starting with a partner. I think that's fair. The software is free, but deciding how your stock codes, warehouses and workflows should work isn't.

Odoo Community

Odoo is the best-known name here, with a set of apps you add as you need them. There are two editions, and telling them apart is the most important part of this section.

Odoo Community is open source under the LGPL. Odoo Enterprise is the paid version, built on top of it. Enterprise needs a licence per user, and Odoo's pricing page shows both a Standard and a Custom plan in pounds. The prices shown include a 12-month discount, so get the full figure before you budget.

• Modular apps. Start with one or two and add more later.
• Invoicing and expenses cover basic workflows.
• A large partner network and app store, for filling gaps.
• Written in Python, on PostgreSQL 13 or later for version 19.

The catch: according to Odoo's own comparison, the full Accounting app, bank synchronisation and OCR are Enterprise features. Studio customisation and some barcode and shop-floor tools are also listed under Enterprise. That matters less on this page, because the plan is to leave accounting in Xero. But if stock staff need barcode scanning, check what you'd get in Community first, because it can change the whole sum.

You can move from Community to Enterprise later, which is a reasonable safety net. It also means some people start free and end up paying per user anyway.

Which one?

My pick is ERPNext, alongside Xero or QuickBooks for the accounting. No features are held back for a paid edition, and there are no per-user fees, so the cost stays predictable as you grow.

• Main drawback: it's a real implementation project, however free the software is.
• Odoo Community instead if you want to start small with one app, or fancy the option of paying for Enterprise later.
• NetSuite or Sage if you're running several companies, currencies or countries, have a finance team that needs proper controls, or have outgrown everything else. Paying for that isn't a mistake.

The UK angle

Where your data lives is a minor point here. Plenty of UK firms run on US-owned cloud systems without any trouble.

Tax is the part that really matters. VAT-registered businesses must keep VAT records and file returns through software compatible with Making Tax Digital. That's another good reason to leave accounting in Xero or QuickBooks. There are UK VAT apps for ERPNext, but I couldn't confirm their HMRC approval status, so check HMRC's list of compatible software before relying on one. I didn't find a reliable answer for Odoo Community, so treat that as unproven too.

An ERP also holds customer, supplier and staff details, so if you self-host, you take on the backups and security. Self-hosting does mean your order history sits in a database you own, and that's worth a lot over 10 years.

Honest drawbacks

• The software is the cheap bit. Mapping your processes, cleaning data and training staff is where the cost and risk sit.
• You'll need a Xero link. Stock and orders in one system and accounts in another need connecting, and that link has to be built and looked after.
• Support is on you. There's no vendor to ring unless you pay a partner.
• Don't assume UK VAT filing is covered. Lean on your accounting package for it.
• Odoo Community has real gaps compared with the Enterprise version people see in demos.
• It's a poor first project. If your basics are shaky, sort those first.

Need help deciding?

If you're weighing up NetSuite against an open-source route, or need one of these connected to your shop and accounts, the team at Dev Partners work on this kind of system and can help you build or customise it.

Sources

• ERPNext on GitHub
• ERPNext features and hosting
• Frappe installation docs
• Odoo on GitHub
• Odoo editions
• Odoo Community vs Enterprise (Odoo blog)
• Odoo pricing
• Odoo source install requirements
• NetSuite UK: how licensing works
• Sage Intacct UK pricing
• HMRC: compatible software for Making Tax Digital for VAT