Design multi-currency pricing end-to-end

Quick Overview

This question evaluates understanding of multi-currency pricing and payments, covering currency selection UX, storage versus presentation currency, exchange-rate sourcing and locking, rounding and localization, tax and fee modeling, caching and cross-channel consistency, and API and data-model design in a distributed marketplace.

System Design: Multi-Currency Price Display and Booking

Context

You are building a global travel marketplace where guests discover listings, view prices, and complete bookings. Users come from many countries, want to pay in their preferred currency, and expect consistent amounts across web/app, emails, invoices, and refunds.

Design the frontend and backend to support multi-currency pricing and booking at scale.

Requirements

Cover the following:

Currency selection UX and defaulting logic
Storage currency vs. presentation currency
When conversions are applied (search/quote vs. checkout), and rate locking
Exchange-rate sources and refresh cadence; fallbacks
Rounding and localization rules (minor units, cash rounding, formatting)
Tax/fee handling (inclusive/exclusive, jurisdiction rules)
Caching strategy across pages and services
Consistency across emails, invoices, and refunds
API design (endpoints, headers, responses) and data model considerations

State any assumptions you need to make.

Design multi-currency pricing end-to-end

Quick Overview