KAYAK

Steve Hafner had already co-founded Orbitz, the online travel agency, in 2000 — so he knew the travel booking world from the inside. What Orbitz was not doing was truly independent price comparison.

After leaving Orbitz, Hafner partnered with Paul English — a veteran software engineer who had built consumer web products — to create something different. Their idea was a meta-search engine: instead of being a travel agency that held inventory, Kayak would search hundreds of booking sites simultaneously and show users where the cheapest price actually lived.

They launched in 2004 out of a Boston garage with a small team. The site was fast, clean, and brutally focused on one thing: finding the cheapest flight.

That focus was the product.

Kayak does not sell flights or hotels directly. It searches other booking sites — airlines, hotels, Booking.com, Expedia, car rental companies — and shows users where the best price is.

When a user clicks through to book, Kayak earns a referral fee from that booking site. It is a classic meta-search model: no inventory, no customer service for the actual booking, just the search layer.

The more accurate and comprehensive the search, the more users come back. The more users come back, the more booking sites pay for the traffic.

In 2012, just before the acquisition, Kayak was generating over $250 million in revenue with solid margins because it had almost no cost of goods — just technology and traffic.

The core product is the Kayak flight, hotel, and car rental search engine — available on web and mobile. Kayak also offers 'Price Alerts,' which notify users when a tracked route drops in price.

'Explore' shows users where they can fly within a budget, which became a popular discovery feature. The 'Trips' app (later integrated into the main app) organized travel itineraries.

Under Booking Holdings, Kayak has maintained its own brand identity and product team while benefiting from the parent company's inventory relationships.

Kayak grew on the back of one insight: travelers hate going to ten different sites to find the best price, and they hate it so much they will use any tool that solves that problem. The growth hack was essentially product quality.

Kayak was genuinely faster and more comprehensive than anything else at the time. They also invested heavily in brand advertising — particularly their memorable, slightly weird TV commercials — which was unusual for a startup in that era.

The 'KAYAK. Search One and Done.' brand message was drilled into travel searchers' heads.

International expansion, partnerships with metasearch networks, and mobile apps all came later, but the core growth driver was just being the best at the one thing they did.

The meta-search model has a built-in structural weakness: you are entirely dependent on the booking sites you search. If Google decides to add flight search (which it did, in 2011 with Google Flights), you lose the most powerful referral source in the world to a competitor who happens to own the internet's main search engine.

Google Flights has been a permanent headache for Kayak ever since. The other challenge is that airlines themselves started suppressing meta-search results or offering different prices to discourage Kayak traffic, which created a constant arms race between Kayak's crawlers and the airlines' pricing APIs.

Early investors included Sequoia Capital and General Catalyst Partners — two of the top-tier Silicon Valley firms that backed Kayak before travel meta-search was proven. Later rounds included Accel Partners and Comcast Ventures.

The company raised about $224 million total before being acquired. Priceline Group (now Booking Holdings) acquired Kayak in 2013 for $1.8 billion in cash — a 4x return on revenue at the time.

The acquisition made sense strategically: Booking Holdings owned the inventory, Kayak owned the discovery layer.