Replacing a legacy ERP with no downtime: a case study
A 50-second case study: how a rental operation's legacy CodeIgniter system was replaced screen by screen with a React web app and React Native field app while it kept running, and switched off in October 2026 with no downtime.
About this video
Told over animated diagrams — no customer or payroll screens are shown, because Rental Pilot's real screens hold live customer and payroll data.
Chapters
Transcript
No narration; on-screen captions, in order:
Replacing a legacy ERP with no downtime — a case study.
A rental operation running since 2008 had everything in one old PHP system — and it could not be switched off, not even for a weekend.
So it was never rewritten in one go. New React web and React Native apps were built next to it, on the same data.
Then they took over one workflow at a time.
The test for each step was not a green build. It was whether every invoice, agreement and audit row still added up.
When the last workflow had moved, the old interface was switched off — October 2026, with no downtime. The old address now sends people to the new app.
Today it runs as Rental Pilot, white-labelled for other rental businesses, and watched on a public status board.
1,400,000 audit-trail rows that had to keep adding up after every step.
Have a system like that? The answer is rarely a rewrite from scratch. mervinc.com.
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