Airbnb / Booking — Notes

Functional

• Search by location, date, filters.
• View listing detail, availability calendar.
• Quote → reserve → pay → confirm.
• Host calendar, smart pricing.
• Messaging, reviews, support.

Non-functional

• Strong consistency: no double-booking.
• p99 search < 500 ms; quote < 300 ms.
• 99.99% availability.

Capacity

• Listings: 7M+ active (Airbnb), Booking 28M+.
• Searches: many millions/day, bursty at peak travel.

Schema

• listings(id, host_id, geo, amenities, price)
• calendar(listing_id, date, state, version)
• bookings(id, listing_id, guest_id, dates[], total, status, idempotency_key)
• reviews(id, listing_id, ratings[], text)

Trade-offs

• Date-range locking: lock the whole window, not single date — careful with concurrency.
• Search vs canonical stores: ES index for search, SQL for truth; sync via CDC.
• Pricing rules are a complex DSL; isolate as a service.

Refs

• Airbnb engineering blog (search ranking, RECs, MySQL sharding via Vitess).
• Booking.com engineering posts on A/B & search.
• ByteByteGo "Design Airbnb".