The core trade-off
This is not a contest with a single winner. Open-source, self-hosted tools give you ownership: the data, the code, and the freedom to modify, at the cost of running the infrastructure. SaaS gives you convenience: managed hosting, support, and a fast start, at the cost of control and a recurring bill. The question is which set of costs your team would rather carry.
"Free" means freedom, not price
A persistent confusion: "free" in free and open-source software refers to liberty — the right to run, study, change, and share the code — not to cost. Open-source marketing tools can and usually do cost money to operate. The license fee is zero; the running cost is not.
Compare total cost of ownership, not sticker price
SaaS has a predictable subscription that scales with contacts or seats. Open source starts cheaper on paper but accumulates total cost of ownership: hosting, the database, monitoring, security, integration work, and the engineering hours to keep it healthy. Neither is automatically cheaper — it depends on your scale and whether you have the team to run infrastructure. Compare the whole picture, not the first line.
| Dimension | Open source, self-hosted | SaaS |
|---|---|---|
| Data | In your own store | On the vendor's servers |
| Cost shape | Hosting + engineering time | Predictable subscription |
| Setup | You deploy and configure | Sign in and start |
| Control | Full — read and modify the code | Whatever the vendor exposes |
| Operations | Yours to run | Managed for you |
Sovereignty is a real consideration
For teams with a strong data-sovereignty stance, one point matters: a US-headquartered SaaS provider can remain subject to the US CLOUD Act, which can compel data access regardless of where the data physically sits. That is a consideration EU-facing teams weigh, not a verdict — but it is one reason ownership and self-hosting appeal. Whatever you choose, remember that hosting location is not compliance: under GDPR you remain the data controller, responsible for your own processing and for any processor you use.