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Service Overview

This project contains a multi-tier microservices application. It is a web-based e-commerce app called “Hipster Shop”, where users can browse items, add them to the cart, and purchase them.


Home Page Checkout Screen
Screenshot of store homepage Screenshot of checkout screen

Service Architecture

Hipster Shop is composed of many microservices, written in different languages, that talk to each other over gRPC and REST API.

We are not endorsing the architecture of Hipster Shop as the best way to build such a shop! The architecture is optimized for learning purposes and includes modern stack: Kubernetes, GKE, Istio, Cloud Operations, App Engine, gRPC, OpenTelemetry, and similar cloud-native technologies.

Architecture ofmicroservices

Find the gRPC protocol buffer descriptions in the ./pb directory.

Service Language Description
frontend Go Exposes an HTTP server to serve the website. Does not require signup/login, and generates session IDs for all users automatically.
cartservice C# Manages the items in the user’s shipping cart by using Redis.
productcatalogservice Go Provides the list of products from a JSON file and the ability to search and retrieve products.
currencyservice Node.js Converts one currency to another, using real values fetched from the European Central Bank. It’s the highest QPS service.
paymentservice Node.js Charges the given credit card info (hypothetically😇) with the given amount and returns a transaction ID.
shippingservice Go Gives shipping-cost estimates based on the shopping cart. Ships items to the given address (hypothetically😇).
emailservice Python Sends users an order-confirmation email (hypothetically😇).
checkoutservice Go Retrieves a user’s cart, prepares the order, and orchestrates payment, shipping, and email notification.
recommendationservice Python Recommends other products based on what’s in the user’s cart.
adservice Java Provides text ads based on given context words.
loadgenerator Python/Locust Continuously sends requests that imitate realistic shopping flows to the frontend.
ratingservice Python3 Manages ratings of the shop’s products. Runs on App Engine.


  • Kubernetes/GKE: The app is designed to run on Google Kubernetes Engine.
  • gRPC: Microservices use a high volume of gRPC calls to communicate to each other.
  • OpenTelemetry Tracing: Most services are instrumented using OpenTelemetry tracers and interceptors which handle trace context propagation through gRPC and HTTP.
  • Cloud Operations APM and SRE: Many services are instrumented with Profiling, Tracing, Debugging, Monitoring, Logging and Error Reporting.
  • Skaffold: A tool used for doing repeatable deployments. You can deploy to Kubernetes with a single command using Skaffold.
  • Synthetic Load Generation: The application demo comes with dedicated load generation service that creates realistic usage patterns on Hipster Shop website using Locust load generator.
  • Google App Engine: PaaS for running Web applications and services.
  • Google Cloud SQL: Fully managed relational database service for MySQL, PostgreSQL and SQL Server.
Last modified May 6, 2021: Update (24e42be5)