Microservices 101: Communication between services

Microservice architecture consists of multiple independent services that often need to communicate with each other. This communication can be achieved in two primary ways: Synchronous Asyncronous Synchronous communication Synchronous communication follows a client-server model, where one service sends a request to another and waits for a response before proceeding. Common protocols REST APIs – resource-based communication using HTTP methods (GET, POST, PUT, DELETE) RPC - Remote Procedure Call. Allows invoking methods on remote services as if they were local. Examples: SOAP - XML-based gRPC - uses binary format for payloads, high performance, Pros & Cons Pros: Simple to use and implement Immediate data retrieval Cons: Tightly coupled - if one service depends on another that is down, the entire operation fails Scalability issues - high traffic can overload serivces Latency - slow response times can create bottlenecks Use cases External API calls Need immediate response (e.g. authentication) Data consistency is critical (e.g. order processing) Asynchronous communication Asynchronous communication uses message brokers as an intermediate service for communication between services. Instead of waiting for an immediate response, a service sends a message to a broker, which another service later processes. Pros & Cons Pros: Loosely coupled - services operate independently, improving scalability High availability and resilience - a service can continue operating even if other services are temporarily down Cons: Increased complexity and maintenance - requires additional infrastructure and message handling Messages ordering & duplication - messages may arrive out of order or be duplicated, requiring deduplication strategies Use cases Event-driven architecture Background processing - immediate response is not required High-load systems - where scalability is a priority

Jan 30, 2025 - 09:45

Microservices 101: Communication between services

Microservice architecture consists of multiple independent services that often need to communicate with each other.

This communication can be achieved in two primary ways:

Synchronous
Asyncronous

Synchronous communication

Synchronous communication follows a client-server model, where one service sends a request to another and waits for a response before proceeding.

Common protocols

REST APIs – resource-based communication using HTTP methods (GET, POST, PUT, DELETE)
RPC - Remote Procedure Call. Allows invoking methods on remote services as if they were local. Examples:
- SOAP - XML-based
- gRPC - uses binary format for payloads, high performance,

Pros & Cons

Pros:

Simple to use and implement
Immediate data retrieval

Cons:

Tightly coupled - if one service depends on another that is down, the entire operation fails
Scalability issues - high traffic can overload serivces
Latency - slow response times can create bottlenecks

Use cases

External API calls
Need immediate response (e.g. authentication)
Data consistency is critical (e.g. order processing)

Asynchronous communication

Asynchronous communication uses message brokers as an intermediate service for communication between services. Instead of waiting for an immediate response, a service sends a message to a broker, which another service later processes.

Pros & Cons

Pros:

Loosely coupled - services operate independently, improving scalability
High availability and resilience - a service can continue operating even if other services are temporarily down

Cons:

Increased complexity and maintenance - requires additional infrastructure and message handling
Messages ordering & duplication - messages may arrive out of order or be duplicated, requiring deduplication strategies

Use cases

Event-driven architecture
Background processing - immediate response is not required
High-load systems - where scalability is a priority