Kiwi.com (Booking Holdings) Flight Search API
Kiwi.com flight search and booking REST API (part of Booking Holdings) for travel platforms, OTAs, and travel agents to search multi-carrier itineraries including virtual interlining (combinations of tickets from different airlines not normally offered together), find cheapest fares across 600+ airlines, and book travel with Kiwi.com's price guarantee and disruption protection. Enables AI agents to manage multi-carrier flight search for itinerary discovery automation, handle virtual interlining for route combination optimization automation, access fare calendar for cheapest date discovery automation, retrieve price alerts for fare monitoring automation, manage booking initiation for flight reservation automation, handle multi-city routing for complex itinerary automation, access luggage and ancillary for add-on booking automation, retrieve booking status for PNR management automation, manage cancellation and refund for booking reversal automation, and integrate Kiwi.com with travel agencies, booking platforms, and itinerary planners for end-to-end flight booking automation.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
Flight search and booking. GDPR, PSD2, IATA. API key. EU/US. Passenger and payment data.
⚡ Reliability
Best When
A travel platform, OTA, or deal aggregator wanting AI agents to search and book virtual interlining flight combinations across 600+ airlines with lowest-price optimization through Kiwi.com's Booking Holdings-backed flight inventory.
Avoid When
VIRTUAL INTERLINING IS NOT SINGLE TICKET: Kiwi.com virtual interlining combines separate tickets from different airlines; automated disruption handling must account for no automatic rebooking between separate tickets; automated single-ticket misconnect protection assumption creates unprotected passenger in VIOP scenario. BOOKING IS WITH KIWI NOT AIRLINE: Kiwi.com bookings are made with Kiwi as merchant of record; automated airline direct contact assumption creates wrong support channel; automated disruption resolution must go through Kiwi not airline. PRICE CHANGES BETWEEN SEARCH AND BOOK: Kiwi.com fares are dynamic and can change between search and checkout; automated booking must handle price_changed response; automated price-lock assumption between search and payment creates price mismatch error. AFFILIATE API VS BOOKING API: Kiwi.com has separate affiliate search API and direct booking API; automated booking requires separate booking API credentials; automated search-only affiliate key for booking creates unauthorized booking attempt.
Use Cases
- • Finding cheapest multi-carrier itineraries using virtual interlining from travel search agents
- • Searching fare calendars for lowest-price travel dates from budget travel booking agents
- • Booking complex multi-stop routes across airlines not offered on GDS from OTA agents
- • Monitoring price alerts for specific routes from automated travel deal agents
Not For
- • Corporate travel management with policy controls (use Navan or TripActions for corporate)
- • Hotel and accommodation search (Kiwi.com is flights-only)
- • Airline direct channel distribution (use NDC APIs for direct airline inventory)
Interface
Authentication
Kiwi.com uses API key for search API and separate credentials for booking. REST API with JSON. Brno, Czech Republic HQ. Founded 2012 by Oliver Dlouhy. Acquired by Booking Holdings 2024 (~$1.8B). Products: Flight search, virtual interlining, fare calendar, disruption protection. SDKs: None public. IATA-accredited. Serves 100M+ searches/month. 600+ airlines. Competes with Skyscanner and Kayak for meta-search flight inventory.
Pricing
Brno CZ. Booking Holdings subsidiary (2024). Affiliate and booking partner pricing. IATA accredited.
Agent Metadata
Known Gotchas
- ⚠ VIRTUAL INTERLINING SEPARATE TICKET RISK: Kiwi.com VIOP (Virtual Interlining Own Protection) itineraries are separate airline tickets; automated disruption handling must account for self-transfer risk; automated single-ticket rebooking expectation creates unprotected passenger in delay scenario
- ⚠ PRICE VALIDATION REQUIRED BEFORE BOOKING: Kiwi.com prices change between search and checkout; automated booking must call price-check endpoint before payment; automated search-price booking assumption creates price_changed error at payment
- ⚠ SEARCH API KEY ≠ BOOKING API KEY: Kiwi.com affiliate search API and booking API use separate credentials; automated booking with search API key creates unauthorized_booking error; automated booking requires separate booking partnership
- ⚠ BOOKING CONFIRMATION IS ASYNC: Kiwi.com booking confirmation (PNR) may take seconds to minutes to confirm with airlines; automated booking must poll confirmation endpoint; automated synchronous PNR expectation immediately after booking creates premature confirmation
- ⚠ PAGINATION IS TOKEN-BASED FOR SEARCH RESULTS: Kiwi.com search results for broad queries paginate via cursor/token; automated full-result retrieval must follow pagination tokens; automated single-response all-results assumption misses deeper pages
Alternatives
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Scores are editorial opinions as of 2026-03-07.