Most microservice implementations are just distributed monoliths. True decoupling requires embracing asynchronous eventual consistency. Here's why relying on standard REST HTTP calls between services is an architectural fatal flaw.
The Tightly Coupled API
When Service A calls Service B synchronously, Service A inherently inherits the availability limits of Service B. If Service B is slow, Service A is slow. This cascading failure pattern is the nightmare of high-scale systems.
// REST Anti-pattern for critical paths
async function processOrder(orderId: string) {
const user = await authService.getUser(); // HTTP GET
const payment = await paymentService.charge(orderId); // HTTP POST
return reserveInventory(orderId);
}Kafka and Eventual Consistency
Instead of HTTP calls, the modern approach dictates pushing domain events to a broker like Kafka. Services react to facts that have already occurred, rather than asking for permission or data.
"If it changes state, emit an event. If it queries state, read from a materialized view."
This article assumes the system will eventually converge. Read more about Temporal.io for Saga patterns to handle rollbacks.