Financial & Commercial
Look-to-Book Ratio (L2B)
The ratio of search requests to actual completed bookings — a core efficiency and cost metric for API-driven platforms.
In simple terms
L2B tells you how many searches it takes, on average, to generate one real booking.
Real-world example
A platform with an L2B of 1000:1 makes 1,000 search API calls for every completed sale.
Why it matters
A high L2B ratio drives up API costs from suppliers who charge per search — many suppliers actively penalize inefficient L2B.
Common mistake
Ignoring L2B ratio until a supplier flags excessive search volume relative to bookings, sometimes triggering fee penalties.
Interview question
Why do suppliers care about a partner's look-to-book ratio, and how would you improve a poor one?
Related terms
API PerformanceCost of SaleCaching