Open source alternatives to SaaS software let a Belgian SME regain control of a licence bill that swells year after year, without sacrificing reliability. Paid cloud use is rising fast: 52.7% of EU enterprises used paid cloud services in 2025, 7.4 points more than in 2023, with office software in SaaS topping the use cases (71.7%) [1]. In Belgium too, cloud and digital services have become commonplace in enterprises [2]. The more subscriptions you stack, the more strategic the question of cost at scale becomes. The right answer is not ideological: it is sequenced.
What is an open source alternative to SaaS software?
SaaS software (Software as a Service) is rented by use: you pay a monthly subscription, often per user, and the vendor hosts and maintains the application. An open source alternative is equivalent software whose code is open, freely installable, and usually without a per-seat licence fee. Many tool categories (collaborative mail, project management, CRM, file storage, dashboards, automation) now have mature open source equivalents.
The decisive nuance lies in the phrase "managed self-hosting". Adopting an open source alternative does not mean your team must install, configure and maintain the software itself. You can delegate installation, deployment and maintenance to a partner, exactly as you already delegate other parts of your IT. You keep the economic advantage and control over the data, without inheriting the operations burden.
Step 1: validate the value with an entry-level SaaS
Before talking about migration, you must prove that a tool genuinely serves your organisation. To trial a new tool, an entry-level SaaS subscription is almost always the smartest first step: low commitment, fast start, no infrastructure investment. Within a few weeks, you know whether the application fits your internal processes, saves time, reduces errors or improves a measurable productivity.
That reflex avoids the classic mistake: heavily building or deploying a tool before checking that it delivers value. SaaS excels precisely in this validation phase, because it turns an investment decision into a simple cancellable subscription. As long as usage volume stays modest, its price stays painless and its convenience unbeatable.
The common-sense rule is therefore: validate the value in SaaS first, consider an alternative afterwards. A tool that does not prove itself deserves neither migration nor self-hosting; it deserves to be dropped.
When should you switch to managed open source self-hosting?
The right trigger is not a subscription's headline price, but the moment usage volume makes the pricing painful. Most SaaS tools bill per seat or per volume: what cost a few dozen euros to trial costs several hundred once the whole team adopts the tool, then more at each growth tier.
When a tool has become essential AND its bill climbs with your headcount or your data, a managed open source alternative can sharply reduce the cost base. The switch is all the more worthwhile when the original SaaS is expensive and its usage intensive. Conversely, a lightly used or already cheap tool does not justify the effort: it only pays off when the annual saving far exceeds the cost of setup and maintenance.
In practice, you keep the same business function, but you stop paying a per-user fee that no longer bears any relation to the value received. The software runs on infrastructure you control, and maintenance becomes a predictable fee rather than a subscription that swells with every hire.
SaaS or self-hosted open source: the honest comparison
Neither approach is superior in absolute terms. SaaS and self-hosted open source answer different priorities, and a credible choice acknowledges the real strengths of each rather than caricaturing one to sell the other.
| Criterion | SaaS (subscription) | Managed self-hosted open source |
|---|---|---|
| Cost at scale | Grows with number of users and volume | Infrastructure cost + maintenance fee, largely decoupled from seat count |
| Start-up | Immediate, zero operations | Selection + initial deployment to plan |
| Operations and availability | Handled by the vendor (contractual SLA) | Delegated to the partner; availability responsibility must be scoped |
| Updates and security | Automatic, vendor side | Applied by the partner (patches, monitoring) |
| Data sovereignty | Depends on the vendor and the location of its servers | Data on controlled infrastructure, in Belgium or the EU |
| Vendor lock-in | Real (formats, pricing, difficult migration) | Low (open code, no per-seat fee) |
| Customisation | Limited to the configuration offered | Extensive, down to the code if needed |
SaaS remains unbeatable to start fast, without a technical team, with support and compliance certifications provided. Self-hosted open source wins on cost at scale, data sovereignty and the absence of lock-in, at the price of an operations responsibility you must entrust to someone. The honest conclusion is therefore not "open source always wins", but "validate in SaaS, migrate the expensive, high-volume tools where data control matters". This tooled decision logic extends the approach set out in our article on IT consulting and digital transformation for SMEs.
The software stack audit: where the real bill hides
A single SaaS rarely costs much. The real spending item is the portfolio: an SME easily accumulates half a dozen to several dozen subscriptions, stacking from a few hundred to several thousand euros per month. Taken one by one, each looks harmless; added together, they form a recurring charge no one really steers.
That is why the high-return approach is to audit the whole IT and software stack rather than optimise an isolated tool. The audit inventories each subscription, its real cost, its usage intensity and its criticality, then identifies the candidates for open source migration for a significant aggregate saving. Often, a few tools concentrate most of the bill: they, as a priority, justify a self-hosted alternative.
This review echoes the role of an outsourced IT department, which consists precisely of putting governance on scattered IT spending. We detail that steering function in our guide on IT outsourcing and the outsourced IT department for an SME.
Why is this switch viable today?
Two linked developments make this approach far more accessible than a few years ago.
First, AI-assisted software engineering and system administration sharply lower the cost of deployment and maintenance. Tasks that once took days of expertise are partly automated, which makes managing self-hosted applications economically worthwhile even for modest organisations.
Second, and as a continuation, the open source ecosystem has gained in quality, maintenance and community momentum. There now exist, off the shelf, real alternatives to mainstream paid tools: you almost never need to build, only to select the right maintained tool and deploy it. The European Commission has in fact made open source a lever of its digital autonomy, under the "Think Open" banner and the principle of "staying in control" of its technology choices [3]. Its study on the economic impact of open source estimates that around 1 billion euros invested in open source in 2018 generated between 65 and 95 billion euros of impact on the European economy, while reducing costs, limiting vendor lock-in and strengthening technological autonomy [4]. What the public sector finds in it, an SME can find at its own scale.
What does it cost and how much can you save?
There is no guaranteed rate or saving, because everything depends on your stack, your volumes and the tools concerned. The reasoning, however, is simple. On the spending side, managed self-hosting shifts the cost: a modest dedicated server (a few dozen euros per month) can host several applications; the bulk of the budget then becomes infrastructure, the initial setup (selecting the right tool for each use, deployment, justifying the choice) and a recurring maintenance fee.
As an illustration, and with no commitment value, a stack costing on the order of 2,000 to 3,000 euros per month in SaaS licences could, once the most expensive tools are migrated, see its cost base brought down to roughly a third to a fifth of that amount, managed maintenance included (for example a maintenance fee on the order of 500 euros per month, plus a setup cost per application). In a typical scenario, the return on investment often sits within a year; but that illustrative figure depends directly on your situation and is never a promise.
Two precautions frame this calculation. On one hand, hosting personal data engages your GDPR responsibility: legal basis, minimisation, data residency in the EU and the framing of sub-processing must be checked, with self-hosting in Belgium or the EU making that residency easier to control [5]. On the other, if you draw on a regional subsidy (enterprise vouchers, Walloon digital grants) to fund the support, none is automatic: always refer to the official source and its eligibility conditions before committing.
How to go about it with an IT partner
The difficulty is not technical but methodological: knowing which tool to validate in SaaS, which to migrate, to which alternative, and who then handles operations. That is precisely the ground of a partner that advises AND executes.
At ITOPS.be, we approach this in two phases. A Blueprint first: audit of the software stack, costing of the subscriptions, identification of the candidates for open source migration and selection of the right tool for each use. A Build next: deployment on controlled infrastructure, followed by maintenance in the form of a fee, without you having to host or administer anything in-house. That continuity between recommendation and implementation avoids the gap between a well-meaning audit and a switch that never lands.
Before any commitment, require the same rigour as for any provider: verifiable references, detailed costing, realistic service level clauses, a reversibility plan and a clear security posture (including NIS2 compliance where it applies). A good partner accepts being challenged on these points, and reasons from the need first before proposing a solution. On that condition, open source alternatives become a lasting cost lever, not a technical gamble.
Frequently asked questions
Should you drop SaaS for open source straight away?
No. The sensible approach is sequenced: first validate a tool's value with an entry-level SaaS subscription, then migrate to a managed open source alternative only the tools whose licence cost becomes heavy at scale. Open source does not win in every case; it wins mainly on the most expensive, highest-volume line items [3].
Is an open source alternative GDPR compliant?
Managed self-hosting of open source can strengthen compliance by keeping data on infrastructure you control, in Belgium or the EU. But the tool alone is not enough: the GDPR obligations (legal basis, minimisation, data residency, sub-processing) remain yours and must be checked case by case [5].
Who hosts and maintains a self-hosted open source tool?
You do not have to do it in-house. An IT partner can select the tool, deploy it on a dedicated server and handle maintenance through a recurring fee. You delegate operations without carrying the administration burden.
How much can you actually save by moving to open source?
It depends entirely on your stack, your volumes and the tools concerned; no figure is guaranteed. As an illustration, a SaaS stack of several hundred to a few thousand euros per month can see its cost base fall sharply once the most expensive tools are migrated, managed maintenance included. Require a detailed estimate tailored to your situation before deciding.
Sources and references
- Eurostat: Cloud computing - statistics on the use by enterprises (2025)
- Statbel: ICT and e-commerce in enterprises
- European Commission: Open source software strategy (Think Open)
- European Commission: Study on the impact of Open Source on the European economy
- Data Protection Authority: GDPR and personal data protection