A travel API is a programmatic interface that lets software search, price and book travel inventory such as flights, hotels, transfers, cars and activities. Supplier APIs connect to one source, like a GDS, an airline or a hotel bedbank. Aggregator APIs normalise many suppliers behind one contract, so you integrate once and get broad content.
What types of travel APIs are there?
| Type | Examples | What you get |
|---|---|---|
| GDS APIs | Amadeus, Sabre, Travelport | Filed airline fares from hundreds of carriers, plus hotels and cars |
| Airline NDC APIs | Individual airlines or NDC aggregators | Airline-built offers, fare bundles, seats and bags (what is NDC?) |
| Low-cost carrier APIs | Direct airline or LCC aggregator connections | Low-cost fares that are often missing from GDSs |
| Hotel bedbank APIs | Hotelbeds, WebBeds, Expedia, Ratehawk | Net hotel rates to mark up and resell |
| Ground and activities APIs | Transfer and car-rental suppliers | Airport transfers, car hire, tours and tickets |
| Unified (aggregator) APIs | TripGic and similar platforms | Many of the above behind one normalised contract |
How does a travel booking API flow work?
Whatever the supplier, bookable travel APIs follow the same shape:
- Search returns options and indicative prices, usually from cache or live supplier calls.
- Price or revalidate confirms the exact price and rules for one option. Prices can change between search and booking, so this step matters.
- Book creates the reservation (a PNR, an NDC order or a hotel booking) with traveller details.
- Pay and fulfil issues the ticket or confirms the voucher.
- Post-booking handles retrieve, change, cancel and refund, plus supplier notifications such as schedule changes.
Demos usually show steps 1 to 3. Operating a travel business depends on steps 4 and 5 working reliably across every supplier.
What to check before choosing a travel API
- Content coverage for your markets: which GDSs, NDC airlines, low-cost carriers and hotel suppliers are live, not "on the roadmap".
- Normalisation: one data model for all suppliers, or different responses you have to map yourself.
- Price accuracy: how often search prices change at booking, and how the API reports it.
- Servicing: cancellations, changes and refunds through the API, not by email.
- Sandbox and documentation: can you build against realistic test data today?
- Limits and look-to-book: search quotas and any penalties for high search-to-booking ratios.
- Commercial model: per-booking fees, subscription or margin, and who holds the supplier contracts.
Is there a free travel API?
Free tiers mostly cover search, reference data or affiliate links. Booking and ticketing need commercial agreements, because someone has to hold the supplier contracts, accreditation and payment risk. The best-known free booking sandbox, Amadeus Self-Service, was shut down on 17 July 2026. See alternatives to the Amadeus Self-Service API.
Direct supplier integrations vs one aggregator
| Direct integrations | Unified travel API | |
|---|---|---|
| Content | Exactly the suppliers you contract | Everything the aggregator has live |
| Build effort | One project and certification per supplier | One integration |
| Maintenance | You track every supplier's version changes | The aggregator absorbs supplier changes |
| Control | Maximum | Shared with the aggregator |
| Best for | High-volume players with a dedicated team | OTAs, apps and platforms that need breadth fast |
The TripGic travel API
Reservationhub's Travel API Service, powered by TripGic, is a unified REST/JSON API covering 700+ airlines across GDS, NDC and low-cost carriers, 2M+ hotels, car rentals, transfers and activities. It includes webhook events for booking changes and a sandbox. If you want a full booking platform instead of an API, compare the options in how to choose travel booking software.
Frequently asked questions
What is a flight booking API?
A flight booking API lets software search flights, confirm prices, create bookings and issue tickets programmatically. It connects to GDSs, airline NDC channels or low-cost carriers, directly or through an aggregator.
What is the difference between a travel API and a booking engine?
A travel API is the data and transaction layer. A booking engine is the application on top of it: search screens, checkout, payments, markups and back office. You can build your own booking engine on an API or use a ready-made one.
REST or XML: which do travel APIs use?
Both. GDSs and NDC are historically XML or SOAP based, while most modern aggregators expose REST/JSON and handle the XML conversion to suppliers internally.
What is a look-to-book ratio?
The look-to-book ratio is the number of searches divided by the number of bookings. Suppliers watch it because every search costs them capacity, and some limit or charge for very high ratios.
How long does a travel API integration take?
It depends on scope. Integrating one unified API is much faster than certifying each GDS, NDC airline and hotel supplier separately, which can take months per supplier.
Get sandbox access to the TripGic API
One REST/JSON integration for flights, hotels, transfers, cars and activities.
Talk to the API team