ProgrammableWeb recently published an updated analysis of the top free and paid Travel APIs available in our directory. Please click here to read the full analysis.
Our API directory now includes 134 travel APIs. The newest is the TakeABreak API. The most popular, in terms of mashups, is the Kayak API. We list 12 Kayak mashups. Below you'll find some more stats from the directory, including the entire list of travel APIs.
In terms of the technical details, REST and XML lead the way. There are 91 travel REST APIs and 25 travel SOAP APIs. Our directory lists 100 travel XML APIs and 51 travel JSON APIs. 
The most common tags within travel are 27 travel booking APIs, 21 travel transit APIs and 14 travel hotel APIs
On the mashup side, we list 497 travel mashups. We named sketchmap as mashup of the day in February. For reference, here is a list of all 134 travel APIs.
Active.com Camping API: Access campground database.
Add To Trip API: Social trip planning service.Track this API
Adriatic.hr API: Croatian travel accommodations service.
AdventureLink API: Travel search and booking service.Track this API
AgentFactor Travel API: Travel booking service.Track this API
Amadeus API: Travel industry transaction processing service.Track this API
Amadeus Cruise API: Cruise line transaction processing service.
BART API: Transit tracking service for San Francisco, California.Track this API
BestParking API: Paid parking location service.Track this API
Bing Traffic API: Traffic information service.Track this API
Bistip API: Travel and purchase service.Track this API
BookingMarkets API: Travel web site Platform.Track this API
BookingSync API: Vacation Rental Booking Service.Track this API
BookIt API: Travel booking services.Track this API
Castilla-La Mancha API: Spain tourism information service.Track this API
Cleartrip API: Travel booking services.Track this API
Cleartrip Hotel API: Hotel booking service.Track this API
Conferma Booking API: UK travel booking and reconciliation service.Track this API
Conferma CSP On-Demand API: UK travel booking service.Track this API
CTA Bus Tracker API: Chicago transit tracking service.Track this API
CTA Customer Alerts API: Chicago transit tracking service.Track this API
Destinde API: Travel information service.Track this API
Deutsche Bahn Openbahn API: German travel Portal.
Dolphin Dynamics API: Travel industry transaction processing service.Track this API
dopplr API: Community travel service.Track this API
EasyToBook API: Hotel Search and Booking Service.Track this API
Escapia Vacation Rental Network API: Vacation rental booking.Track this API
Evature Travel Search API: Free text travel search query service.Track this API
EveryTrail API: Travel experience platform.Track this API
Expedia API: Travel booking service.Track this API
Eyewitness Guide to London API: Travel guide to London.Track this API
FlightAware API: Live flight aircraft tracking.
FlightCaster API: Flight delay predictor.Track this API
FlightLookup API: Flight Schedules and Airport Lookup Service.Track this API
FlightStats API: Live flight aircraft and delays tracking.Track this API
FlightView API: Live flight aircraft and delays tracking.Track this API
Flightwise API: Flight tracking service.Track this API
FlyOnTime API: Flight time and delay Resource.Track this API
GetYourGuide API: Travel tours and activities booking service.Track this API
GroundLink API: Ground transportation service.Track this API
HipGeo API: Trip tracking and recording application.Track this API
HotelBeds API: Travel accomodations service.Track this API
HotelsCombined API: Hotel comparison search / aggregator.Track this API
Hotwire API: Travel deals and historical price data from Hotwire.com.Track this API
Hotwire Hotel Shopping API: Hotel shopping service.Track this API
Hotwire Rental Car Shopping API: Rental car shopping service.Track this API
Hotwire Travel-Ticker Deals API: Travel deals service.Track this API
InKnowledge Taxi Fare Calculator API: Taxi fare estimation service.Track this API
iSeatz API: Customized online travel and entertainment solutions.Track this API
iwannagothere API: Community-based travel guide.Track this API
jakdojade.pl API: Polish transit service.
Jeppesen Journey Planner API: Trip planning service.Track this API
Kayak API: Travel search service.Track this API
Kelkoo API: Comparison shopping service.Track this API
Kijubi API: Activity marketplace service.Track this API
King County Busses API: Transit tracking service.Track this API
Kumutu API: Adventure sports distribution service.Track this API
Lonely Planet API: Travel guidebook content services.Track this API
Mapnificent API: Public transportation map service.Track this API
Massachusetts Port Authority API: Data feeds for Massachusetts Port Authority.Track this API
Merrcury API: Travel shopping service.Track this API
Metro Traffic API: Real-time traffic data service.Track this API
Metro Trip Planner API: Los Angeles Metro transit information.Track this API
Minube API: Social travel recommendation site.Track this API
Moneydirect API: Multi channel payment platform.Track this API
MTA API: New York City Transit service.Track this API
MyBikeLane API: Read-Only API for MyBikeLane and UncivilServants Database.Track this API
MyTravelToolbox API: Travel website application.Track this API
MyTTC API: Realtime Toronto transit information.Track this API
NAC Real-time Routing API: Realtime driving directions service.Track this API
NAVTEQ Traffic API: Local traffic information service.Track this API
Nevistas News API: Hotel and Travel News Search Service.Track this API
Nextstop API: Travel recommendation service.Track this API
NileGuide API: Travel research and planning service.Track this API
OneBusAway API: Realtime Seattle transit information.Track this API
ParkWhiz API: Access to parking and event data.Track this API
Paynoy API: Philippines deal service.Track this API
PilotOutlook API: International airport data.Track this API
Placr API: UK transit data service.
Planyo API: Online reservation service.Track this API
Pocket Village API: Travel search and booking service.Track this API
Postcode Anywhere Distances and Directions API: Business travel data service.Track this API
Postcode Anywhere Route Optimisation API: Find best route between locations.Track this API
Public Transit Data Community API: US transit data feeds service.
Qype API: Local reviews service.Track this API
RatePubs API: Pub and bar reviews services.Track this API
Rezgo API: Travel tour booking service.Track this API
Rome2rio API: Travel itinerary search service.Track this API
Roomorama API: Short-term travel rental service.Track this API
Rutamina API: Travel route planning and sharing.Track this API
Sabre API: Travel industry transaction processing service.Track this API
SilverRail Technologies API: Rail travel planning service.Track this API
Skyscanner API: Flight and travel search engine.
SmartTravelDeals API: Travel offer publishing and search.Track this API
SMSMyBus API: Madison transit service.Track this API
StrikeIron Address Distance API: Calculation of distances between addresss.Track this API
Superbreak API: Travel booking services.Track this API
TakeABreak API: Australian vacation/holiday property Web Service.Track this API
Taxi Magic API: Taxi booking service.Track this API
TÃ¥gtider Trains API: Sweden train schedule lookup service.
Tgels API: White-label airfare search and comparison service.Track this API
Tixik API: Famous places GPS services.Track this API
to.uri.st API: Travel and tourist database services.
TourCMS Marketplace API: Online travel reservation service.Track this API
TouricoHolidays API: Travel booking service.
TrafficViolators API: Community traffic watch initiative.Track this API
Transport for London API: UK transportation service.Track this API
Travel Booking Engine API: Online travel booking service.Track this API
Travel Connectivity XML API: Travel content and data provider.Track this API
Travel IQ API: German travel booking service.Track this API
TravelFusion API: Travel Flight Booking API.Track this API
Travelport API: Travel booking service.Track this API
TravEnjoy API: Travel search service.Track this API
Trazzler API: Travel recommendation service.Track this API
TriMet API: Transit tracking service for Portland, Oregon.Track this API
TripAuthority API: Hotel reservation service.Track this API
TripIt API: Online travel itinerary service.Track this API
Tripl API: Social travel service.Track this API
TripSay API: Social travel search and recommendations service.Track this API
TripTracker API: Trip Tracking Service.Track this API
Tube Updates API: Unofficial London transit service.Track this API
ValueCommerce Travel API: Travel web service.Track this API
ViaMichelin API: Mapping, directions, and travel booking services.Track this API
Viator API: Travel affiliate services.Track this API
Volkswagen Reviews Network API: Chinese city and shopping guide.Track this API
Waze API: Social navigation application.
Wcities API: Travel guide and information service.Track this API
Webcams.travel API: Webcam repository.
Where I've Been API: Social mapping and travel service.Track this API
Winnipeg Transit API: Transit data service.Track this API
WMATA API: DC Transit Service.Track this API
Yahoo Travel API: Online travel services.Track this API
Yapta API: Airfare Tracking Service.Track this API
Zoombu Fly API: Travel search service.Track this API
