"What does Mendix actually cost?" A tricky question, because the answer depends on four things: how many apps, how many users, which licence type, and which add-ons. No vendor will give you a simple price tag, and with good reason, it genuinely depends on your situation. What we can do is share the patterns we've seen dozens of times in migration conversations.
Remember: this isn't a quote. It's a calculation.
The three cost lines you underestimate
Mendix costs are more than "a few hundred euros per user per month". Always think in three blocks:
- Platform licences (fixed). Per environment or per app, often with a minimum commitment.
- Per-user licences (variable). Scale with success. More users, bigger bill.
- Add-ons and marketplace modules. Audit logging, advanced workflows, document generation, faster than building it yourself, but recurring.
Add your own costs on top: developers (Mendix specialists are scarce and expensive), hosting (partly via the platform, partly your own), and a fresh budget conversation every time the price list changes.
A five-year rule of thumb
Say you have an internal app with 100 active users, growing slowly. In year 1 you mostly pay for platform licences; user numbers are still low. Attractive. In year 3 your user count has doubled; in year 5 it has tripled. Mendix costs rise with it, even though the functionality hardly changes anymore.
What we see again and again: somewhere between year 2 and year 4 the balance tips. What you saved in year 1 you've paid back in licences by year 3. And those licences don't stop, they keep ticking, year after year, while your app is essentially finished.
What a Java stack puts on the other side
A Java and Spring Boot stack asks for more engineering up front. Expect a larger initial investment (think weeks to months, not days). In return:
- No platform licences. Open-source. Serving 200 or 2,000 users costs nothing extra.
- Cheaper labour market. Java developers are everywhere; Mendix specialists are scarce.
- Ownership. You own the code, not a set of models inside someone else's platform.
- No price-list risk. A vendor can change its licensing model, and does, now and then. Open-source doesn't.
Look at it this way: with Mendix you rent the building year after year. With Java you buy it, once. Renting is fine for an MVP, less so for your headquarters.
When is migration financially smart?
Three heuristics that hold up in practice:
- User numbers grow faster than the functionality. You're paying for "more people on the same system", a classic migration moment.
- The system needs to last another 5+ years. Total licence costs then outpace the migration investment.
- You're hitting platform limits. Custom Java actions, JavaScript widgets and home-grown connectors pile up, you're already building custom software on a platform that isn't really meant for it.
One or more of those match your situation? An honest comparison or a Mendix scan is well worth the time.
How to do your own calculation
Not by requesting a vendor quote. By looking five years out, not one. Add up platform + users + add-ons + developers, assume 15–25% annual user growth, and compare with a Java build plus maintenance. If the five-year outcome is roughly equal, stay on Mendix. If Java is clearly lower, you're not the first to notice.
Want us to work this out with you for your specific situation? Book a free legacy scan, we'll look at one app and give you an honest number instead of a sales pitch.