UK online retailers made the most of high volumes of sales during the Christmas period with almost 100% availability.
Website monitoring company NCC Group found that the average UK retail website had 99.88% uptime across Christmas Eve, Christmas Day and Boxing Day.
Website average download time was 9.9 seconds.
According to figures from the British Retail Consortium (BRC), online retailers saw 26.5% growth in December, up from 16.9% in November and the highest level of growth in 2009.
Data provided by Retail Decisions for IMRG showed sales increased 29% to £132m on Christmas Day 2009, compared with the previous year. Sales of £281m were made on Boxing Day.
The research also revealed that 41.3% of people are predicted to spend more online next Christmas due to a positive online experience this year.
Bob Dowson, director at Site Confidence, said online retailers had to test websites to ensure they were ready for Christmas. "Etailers responded accordingly, load testing their sites to ensure they could cope with the expected hike in website visitors, while using website monitoring to make sure that user experience remained unaffected by poor performance."
He added that 2010 is likely to continue to be tough on the high street and websites will become more important for retailer revenues.