Your OutSystems Team and Your React Team Are in the Same Room. They Still Can't Talk.
Companies migrating from OutSystems to React face an invisible wall: two development teams that cannot share knowledge. Here is why and how to bridge the gap.
The scene
You've made the decision. OutSystems costs too much, the talent pool is shrinking, and your company's future is in modern, open-source technology. You hire React developers. You sit them next to your OutSystems team. You say: "Rebuild what we have."
Six months later, you're behind schedule. The React team is frustrated. The OutSystems team feels defensive. And nobody can explain why a migration that seemed straightforward has turned into a slow, painful excavation.
Here's what happened.
The invisible wall
OutSystems and modern development don't just use different languages. They live in different worlds.
There's no source code to hand over. In a normal technology migration — say, Java to TypeScript — the new team reads the old codebase. They trace the logic. They port it, function by function. There's Git history showing why decisions were made. There are comments, tests, documentation.
OutSystems has none of this. The "source" is a visual model inside Service Studio. It's not a file your React developers can open. It's not on GitHub. There are no diffs, no blame annotations, no commit messages explaining that weird edge case in the payment flow.
The React team can only see the output. Your React developers open the web application in their browser. They inspect the DOM. They watch network requests. They're essentially reverse-engineering a live application by looking at its surface — the same way you'd try to understand a car engine by watching the wheels turn.
They miss the server actions. They miss the entity relationships. They miss the BPT workflows running in the background. They miss the timer-based processes that sync data at 3am. They miss the Forge component that handles a critical edge case nobody documented.
The OutSystems team can't explain it in React terms. Your OutSystems developers know exactly how the application works. But they think in entities, server actions, and screen aggregates. When a React developer asks "what does this API endpoint do?", the OutSystems developer thinks "that's not an API endpoint, that's a server action exposed as a REST service that calls three other server actions, one of which triggers a BPT process."
The mental models are incompatible. It's not that anyone is bad at their job. It's that the abstraction layers don't align.
And then there's the cultural tension. Let's be honest about this one. React developers often look at OutSystems and see a toy — a drag-and-drop tool that "real" developers wouldn't use. OutSystems developers see React developers dismissing years of complex business logic because it was built in a visual IDE instead of vim.
Neither perspective is fair. Both are common. And it makes collaboration harder than it should be.
What actually gets lost
When we've analyzed migrations that were attempted this way — two teams, same room, good intentions — the same things get lost every time:
1. Business rules buried in server actions A single OutSystems server action can contain complex branching logic with dozens of conditions. This gets built up over years, often by different developers, each adding their edge case. Without reading the actual model, the React team implements the "happy path" and misses the 47 exceptions.
2. Data relationships that aren't visible from the UI OutSystems entity relationships drive everything — validation rules, cascading deletes, default values, calculated attributes. The React developer sees a form with 10 fields. They don't see the 6 entities behind it, the 3 foreign keys, and the 2 computed values.
3. Background processes Timers, BPT workflows, scheduled jobs — these are invisible from the frontend. The React team builds a beautiful new UI and goes live. Two weeks later, finance reports that the nightly reconciliation stopped working. Nobody told the React team it existed because it runs in the background.
4. Integration contracts OutSystems wraps external services in REST/SOAP consumers. The React team needs to recreate these, but the exact request/response transformations, error handling, and retry logic are locked inside the OutSystems model.
Why "just document everything" doesn't work
The obvious solution is: have the OutSystems team write documentation before the React team builds. In practice, this fails because:
- OutSystems developers don't document in code — the platform doesn't encourage it. The visual model IS the documentation, supposedly.
- Documentation is always incomplete — you only discover what's missing when the new system breaks in production
- It takes almost as long as rebuilding — thoroughly documenting a complex application is essentially the same effort as understanding it for migration
The bridge that's missing
The core problem is that nobody in the room can produce a complete, accurate, technology-neutral description of what the OutSystems applications actually do.
The OutSystems team knows the applications through the lens of Service Studio. The React team knows modern development but can't access the source. Management knows the business requirements — from five years ago, before 200 change requests.
What you need is a way to extract the complete logic — every entity, every business rule, every workflow, every integration — into a format that both teams can read and agree on. A shared blueprint.
That's the gap we fill.
Our proprietary assessment technology produces exactly this: a complete, readable map of your OutSystems applications. Your React team gets a clear specification to build from. Your OutSystems team validates that nothing was missed. Your managers get accurate timelines because the scope is actually understood.
No more archaeology. No more lost-in-translation. No more surprises in production.
Book a free assessment → — We'll produce a blueprint of your OutSystems applications that both teams can finally read.