System design case studies that connect product requirements to architecture, data models, APIs, failure modes, security, observability, and scale.https://rahmankutlu.github.io/build-real-world/2026-09-27T00:00:00Zhttps://rahmankutlu.github.io/build-real-world/projects/ecommerce/2026-09-27T00:00:00Z

Catalog, inventory, checkout, fulfillment, and returns without overselling.

https://rahmankutlu.github.io/build-real-world/projects/food-delivery/2026-09-27T00:00:00Z

Coordinate customers, restaurants, couriers, menus, dispatch, and live delivery state.

https://rahmankutlu.github.io/build-real-world/projects/ride-hailing/2026-09-27T00:00:00Z

Match riders and drivers under location churn and acceptance races.

https://rahmankutlu.github.io/build-real-world/projects/hotel-pms/2026-09-27T00:00:00Z

Property operations, room inventory, reservations, folios, and housekeeping across time zones.

https://rahmankutlu.github.io/build-real-world/projects/appointment-saas/2026-09-27T00:00:00Z

Multi-tenant scheduling with availability rules, holds, reminders, and calendar sync.

https://rahmankutlu.github.io/build-real-world/projects/project-management/2026-09-27T00:00:00Z

Tenant-safe projects, tasks, comments, permissions, activity, and collaborative updates.

https://rahmankutlu.github.io/build-real-world/projects/video-streaming/2026-09-27T00:00:00Z

Ingest, transcode, package, authorize, and deliver on-demand video globally.

https://rahmankutlu.github.io/build-real-world/projects/social-network/2026-09-27T00:00:00Z

Create social graphs and feeds while controlling fan-out, abuse, and privacy.

https://rahmankutlu.github.io/build-real-world/projects/cloud-file-storage/2026-09-27T00:00:00Z

Secure resumable uploads, hierarchy, sharing, versioning, and background scanning.

https://rahmankutlu.github.io/build-real-world/projects/payment-platform/2026-09-27T00:00:00Z

Safely orchestrate provider payments, idempotency, ledger entries, webhooks, and reconciliation.

https://rahmankutlu.github.io/build-real-world/patterns/idempotency-keys/2026-09-27T00:00:00Z

Make retried commands return one durable outcome.

https://rahmankutlu.github.io/build-real-world/patterns/outbox-pattern/2026-09-27T00:00:00Z

Commit a domain change and a message-to-publish together.

https://rahmankutlu.github.io/build-real-world/patterns/saga-pattern/2026-09-27T00:00:00Z

Coordinate a long workflow through compensatable local transactions.

https://rahmankutlu.github.io/build-real-world/patterns/optimistic-locking/2026-09-27T00:00:00Z

Reject stale writes with a version precondition.

https://rahmankutlu.github.io/build-real-world/patterns/pessimistic-locking/2026-09-27T00:00:00Z

Serialize a short critical section with database row locks.

https://rahmankutlu.github.io/build-real-world/patterns/retry-with-backoff/2026-09-27T00:00:00Z

Retry transient work without amplifying an outage.

https://rahmankutlu.github.io/build-real-world/patterns/circuit-breaker/2026-09-27T00:00:00Z

Stop spending resources on a dependency that is persistently failing.

https://rahmankutlu.github.io/build-real-world/patterns/rate-limiting/2026-09-27T00:00:00Z

Bound resource use and abuse across meaningful identities.

https://rahmankutlu.github.io/build-real-world/patterns/cache-aside/2026-09-27T00:00:00Z

Read through an application-managed cache while keeping a durable source of truth.

https://rahmankutlu.github.io/build-real-world/patterns/cqrs/2026-09-27T00:00:00Z

Use separate command and read models when their needs truly diverge.

https://rahmankutlu.github.io/build-real-world/patterns/event-sourcing/2026-09-27T00:00:00Z

Persist domain events as the primary state history.

https://rahmankutlu.github.io/build-real-world/patterns/webhooks/2026-09-27T00:00:00Z

Deliver signed at-least-once events between independently operated systems.

https://rahmankutlu.github.io/build-real-world/patterns/distributed-locks/2026-09-27T00:00:00Z

Coordinate across owners only when database constraints or partition ownership cannot.

https://rahmankutlu.github.io/build-real-world/patterns/pagination/2026-09-27T00:00:00Z

Traverse changing datasets with stable keyset cursors.

https://rahmankutlu.github.io/build-real-world/patterns/multi-tenancy/2026-09-27T00:00:00Z

Make tenant ownership explicit in identity, schema, authorization, caches, and operations.

https://rahmankutlu.github.io/build-real-world/patterns/background-jobs/2026-09-27T00:00:00Z

Run durable, retryable work outside an interactive request.

https://rahmankutlu.github.io/build-real-world/patterns/audit-logs/2026-09-27T00:00:00Z

Record who did what, to which object, when, and why.