From REST to GraphQL without touching the frontend
A network of private outpatient clinics
The constraint
Dozens of REST microservices and a frontend that depended on their contracts. The move to GraphQL had to happen with the service live, without rewriting the interfaces and without changing the answers patients see.
The intervention
A serverless Node gateway acts as an anti-corruption layer: it translates the new GraphQL schema into the contract the frontend knows. Each handler was ported one to one with parity tests, and the ERP integration is governed by a switch that, when needed, turns it off and notifies people.
What changed
Migration in progress by domain, with no interruptions. Token signatures moved to asymmetric keys during review, and the client's team adds new endpoints on the architecture we set up.
Describe the system. We'll tell you what we see.
Ten minutes, one question at a time. At the end, our honest read of the case. It's the filter, before the call.