# Architecture & Canonical Engineering

Production-grade architecture guides for search, offers, booking, payments, reconciliation and servicing.

## Pages

- [ACP, UCP, AP2, MPP, x402, MCP and A2A: Protocol Landscape for Travel](https://metasearch.com.tr/en/learn/agentic-commerce-protocol-landscape.md): Compare ACP, UCP, AP2, MPP, x402, MCP and A2A by the architecture layer they solve in agentic travel commerce.
- [Agentic Travel Authorization, Mandates and Human-in-the-Loop](https://metasearch.com.tr/en/learn/agentic-travel-authorization-mandate-hitl.md): Design user intent, mandates, delegated authority and human-in-the-loop checkpoints for AI-driven travel purchase and servicing side effects.
- [Agentic Travel Reference Architecture](https://metasearch.com.tr/en/learn/agentic-travel-reference-architecture.md): Design AI agent → search → offer → reprice → confirmation → payment → booking → servicing with travel-specific authorization, idempotency and audit boundaries.
- [Agentic Travel Servicing, Consent and Auditability](https://metasearch.com.tr/en/learn/agentic-travel-servicing-auditability.md): Design agent-driven cancellation, refund and servicing with explicit consent, traceability, versioned evidence and post-booking authorization boundaries.
- [Agentic Travel Transaction Safety](https://metasearch.com.tr/en/learn/agentic-travel-transaction-safety.md): Prevent duplicate booking and payment caused by agent loops, retries and tool invocation using idempotency, side-effect guards and UNKNOWN-aware recovery.
- [Booking Lifecycle Event Model](https://metasearch.com.tr/en/learn/booking-lifecycle-event-model.md): Design travel-booking state around create, confirm, modify, cancel, fail and reconcile events with explicit ordering and idempotency.
- [Booking Timeout and UNKNOWN Outcome Recovery](https://metasearch.com.tr/en/learn/booking-timeout-unknown-outcome-recovery.md): Recover ambiguous travel-booking timeouts with UNKNOWN state, authoritative lookup, reconciliation and safe retry gates.
- [Cache and Price Freshness in Metasearch](https://metasearch.com.tr/en/learn/cache-price-freshness.md): Design travel-metasearch caching with realistic search load, adaptive TTLs, selective live rechecks, stale-price risk, observability and production trade-offs.
- [Canonical Hotel Entity Model](https://metasearch.com.tr/en/learn/canonical-hotel-entity-model.md): Design a canonical hotel identity layer that maps multiple supplier property records into one traceable entity with provenance and merge history.
- [Canonical Offer, Order and Booking State Model](https://metasearch.com.tr/en/learn/canonical-offer-order-booking-state-model.md): Design canonical Offer, Order and Booking lifecycle boundaries with an explicit booking state machine for travel integrations.
- [Direct Connect Architecture: Supplier to OTA and Metasearch](https://metasearch.com.tr/en/learn/direct-connect-architecture.md): Design supplier-to-OTA/metasearch direct connections around ownership, mapping, retry and reconciliation.
- [GDS vs Bedbank vs Direct Connect: Distribution Topology Guide](https://metasearch.com.tr/en/learn/gds-bedbank-direct-connect.md): Compare GDS, bedbank/B2B marketplace and direct-connect models across inventory ownership, coverage, booking lifecycle and operations.
- [GDS vs NDC: Airline Distribution Architecture](https://metasearch.com.tr/en/learn/gds-vs-ndc.md): Compare GDS and NDC across airline shopping, Offers/Orders, content ownership, servicing and integration architecture.
- [Hotel ARI Sync: Restrictions, Stop-Sell, CTA/CTD and Reconciliation](https://metasearch.com.tr/en/learn/hotel-ari-sync-restrictions.md): Design Availability, Rates & Inventory flows with restrictions, stop-sell, CTA/CTD, idempotency, reservation delivery and reconciliation.
- [Idempotency and Duplicate Booking Prevention](https://metasearch.com.tr/en/learn/idempotency-duplicate-booking-prevention.md): Design idempotency boundaries and duplicate-booking safeguards across travel booking, payment, cancellation and refund operations.
- [Long-Tail Refresh Scheduling](https://metasearch.com.tr/en/learn/long-tail-refresh-scheduling.md): Schedule travel inventory refreshes by demand, volatility, freshness and cost instead of using one fixed interval for every entity.
- [Multi-Supplier Hotel Search Architecture](https://metasearch.com.tr/en/learn/multi-supplier-hotel-search-architecture.md): Design hotel search across multiple suppliers using fan-out, normalization, deduplication, timeout budgets, partial results and ranking.
- [Offer Identity & Offer Fingerprint Design](https://metasearch.com.tr/en/learn/offer-fingerprint-design.md): Design deterministic travel-offer fingerprints across provider, room/rate, policy and search-context dimensions without coupling identity to price.
- [Package Holiday Distribution Architecture](https://metasearch.com.tr/en/learn/package-holiday-distribution-architecture.md): Model hotel, flight, transfer, bundle identity, pricing, cancellation and booking lifecycle for package-holiday distribution.
- [Payment + Booking Distributed Transaction](https://metasearch.com.tr/en/learn/payment-booking-distributed-transaction.md): Model payment and supplier booking as a distributed transaction using authorization, capture, compensation, UNKNOWN outcomes and reconciliation.
- [PMS vs CRS vs Channel Manager: What Is the Difference?](https://metasearch.com.tr/en/learn/pms-crs-channel-manager.md): Compare PMS, CRS and Channel Manager roles in hotel distribution by inventory ownership, ARI, reservation flow, mapping and source-of-truth boundaries.
- [Price Observation & Event Model](https://metasearch.com.tr/en/learn/price-observation-event-model.md): Model travel pricing as timestamped observations and change events instead of only overwriting mutable current-price state.
- [Provider Fallback Strategy](https://metasearch.com.tr/en/learn/provider-fallback-strategy.md): Design provider fallback for travel search and booking across outages, timeouts, stale cache and alternate suppliers.
- [Provider Health Scoring Model](https://metasearch.com.tr/en/learn/provider-health-scoring-model.md): Build an explainable travel-provider health score using latency, success, freshness, price accuracy, coverage and handoff quality.
- [Search Fan-Out & Partial Results Architecture](https://metasearch.com.tr/en/learn/search-fanout-partial-results-architecture.md): Manage parallel travel-provider calls with latency budgets, bounded concurrency, early useful results and controlled final merging.
- [Search Result Ranking Architecture](https://metasearch.com.tr/en/learn/search-result-ranking-architecture.md): Design explainable travel ranking that separates relevance, normalized price, offer quality, provider reliability and commercial constraints.
- [Sponsored & Commercial Ranking Governance](https://metasearch.com.tr/en/learn/sponsored-commercial-ranking-governance.md): Separate sponsored placement, bids and commissions from organic relevance with transparent, auditable metasearch ranking governance.
- [Travel Supplier Adapter Pattern](https://metasearch.com.tr/en/learn/supplier-adapter-pattern.md): Isolate hotel and flight provider contracts behind adapters with explicit DTO boundaries, normalization, error taxonomy and versioning.
- [Supplier Latency and Timeout Budgets in Metasearch](https://metasearch.com.tr/en/learn/supplier-latency-timeout-budgets.md): Design timeout budgets, parallel supplier calls, partial-result handling, circuit breakers and latency SLOs for hotel and flight metasearch search pipelines.
- [Sync vs Async Travel Booking Architecture](https://metasearch.com.tr/en/learn/sync-vs-async-travel-booking.md): Compare synchronous and asynchronous travel booking orchestration across latency, recovery, UX and provider capabilities.
- [Travel Booking Saga and Compensation Patterns](https://metasearch.com.tr/en/learn/travel-booking-saga-compensation-patterns.md): Design Saga and compensation patterns for travel booking, payment, cancellation and refund workflows where rollback is impossible.
- [Travel Event Reconciliation Architecture](https://metasearch.com.tr/en/learn/travel-event-reconciliation-architecture.md): Design deterministic reconciliation across booking, payment, cancellation and supplier events with explicit authority and audit rules.
- [Travel Observability, Trace and Correlation Model](https://metasearch.com.tr/en/learn/travel-observability-trace-correlation-model.md): Trace travel transactions from search through booking and servicing using correlation IDs, distributed traces, metrics and structured domain events.
- [Travel Offer Data Lineage](https://metasearch.com.tr/en/learn/travel-offer-data-lineage.md): Trace a travel offer from supplier response through normalization, cache, ranking and booking handoff with explicit lineage identifiers.
- [Travel Payment Ownership: Merchant of Record, Seller of Record and Collect Models](https://metasearch.com.tr/en/learn/travel-payment-ownership-models.md): Separate Merchant of Record, Seller of Record, agency collect, hotel collect and pay-at-property models across booking and reconciliation.
- [Travel PII and Passenger Data Boundaries](https://metasearch.com.tr/en/learn/travel-pii-passenger-data-boundaries.md): Design safe boundaries for passenger identity, contact, payment and travel-document data across search, booking, logging and provider integrations.
- [Cache Invalidation Patterns for Travel Pricing](https://metasearch.com.tr/en/learn/travel-pricing-cache-invalidation-patterns.md): Design TTL, event invalidation, stale-while-revalidate and live-reprice boundaries for hotel and flight pricing.
- [Travel Search → Offer → Reprice → Booking Reference Architecture](https://metasearch.com.tr/en/learn/travel-search-offer-booking-reference-architecture.md): Design an end-to-end reference architecture for travel search, canonical offers, repricing, payment and booking across supplier integrations.
- [Travel Servicing Architecture](https://metasearch.com.tr/en/learn/travel-servicing-architecture.md): Model post-booking change, cancellation, refund, exchange, ancillary and schedule-change workflows with a canonical servicing architecture.
- [How the Turkey Travel Distribution Ecosystem Works](https://metasearch.com.tr/en/learn/turkey-travel-distribution-ecosystem.md): A technical guide to how travel supply moves from PMS/CRS/PSS through GDS, NDC, bedbanks and channel managers into OTA and metasearch layers in Turkey.
- [Webhook vs Polling Reconciliation](https://metasearch.com.tr/en/learn/webhook-vs-polling-reconciliation.md): Design webhook, polling and reconciliation roles for travel booking systems, including duplicate, out-of-order and missing-event recovery.