##### Question Design a product catalog service for an e-commerce platform: define high-level API endpoints (CRUD, search, bulk import), relational schema (including a self-join to model category hierarchies), and discuss scalability, caching, and consistency.

This question evaluates a candidate's competence in large-scale system design, relational data modeling, API design, search and indexing, caching strategies, and consistency management for a read-heavy e-commerce product catalog.

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System Design questions require understanding of core concepts and practice. PracHub provides solutions with explanations to help you master system design interviews.

What difficulty level is this interview question?

This is a hard difficulty System Design question, commonly asked during Onsite rounds at Instacart.

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This question is commonly asked for Software Engineer candidates at Instacart during technical interviews.

Design product catalog service | Instacart Interview Question

System Design: Product Catalog Service for an E-commerce Platform

Context

You are designing the product catalog service for a large consumer e-commerce platform with millions of SKUs and a hierarchical category tree (e.g., Grocery > Produce > Berries). The system is read-heavy, supports frequent merchant updates and bulk imports, and powers product detail pages, category browsing, and search.

Requirements

APIs
- CRUD for products, categories, and variants/SKUs.
- Full-text search with filtering, sorting, pagination, and faceting.
- Bulk import (asynchronous), with job tracking and idempotency.
Data Model
- Relational schema as the source of truth (PostgreSQL/MySQL).
- Category hierarchy modeled via a self-join.
- Many-to-many product–category mapping, support for variants, attributes, media, and brands.
Non-Functional
- Scalability for high read QPS and periodic write spikes (e.g., bulk imports, price updates).
- Caching strategy (object cache, edge cache, search engine) and invalidation.
- Consistency across the relational DB, cache, and search index; read-your-writes for admins.

Deliverables:

Define high-level API endpoints (CRUD, search, bulk import) with request/response examples.
Propose a relational schema including a self-join for category hierarchies.
Discuss scalability, caching, and consistency strategies.

Context

Requirements

APIs

CRUD for products, categories, and variants/SKUs.
Full-text search with filtering, sorting, pagination, and faceting.
Bulk import (asynchronous), with job tracking and idempotency.

Data Model

Relational schema as the source of truth (PostgreSQL/MySQL).
Category hierarchy modeled via a self-join.
Many-to-many product–category mapping, support for variants, attributes, media, and brands.

Non-Functional

Scalability for high read QPS and periodic write spikes (e.g., bulk imports, price updates).
Caching strategy (object cache, edge cache, search engine) and invalidation.
Consistency across the relational DB, cache, and search index; read-your-writes for admins.

Deliverables:

Define high-level API endpoints (CRUD, search, bulk import) with request/response examples.

Propose a relational schema including a self-join for category hierarchies.

Discuss scalability, caching, and consistency strategies.

Design product catalog service

Quick Overview

System Design: Product Catalog Service for an E-commerce Platform

Context

Requirements

Solution

Comments (0)

Design product catalog service

Quick Overview

System Design: Product Catalog Service for an E-commerce Platform

Context

Requirements

Solution

Comments (0)