The Results Plus service lets teachers map grades against national averages and provides pupils with a breakdown of their performance online.
After logging in, pupils see their result on a "grade-o-meter", as well as how they performed on individual questions. Teachers can also look at a "skills map" which shows where their class needs to do more work.
But there are concerns that the technology, being piloted by the exam board Edexcel, could increase the demand for regrades. Heads complained last month that the exam system was close to collapse because of the number of papers sent for remarking.
Carole Whitty, deputy general secretary of the National Association of Head Teachers, said the system would put pressure on teachers to double-check pupils' results and was therefore likely to increase appeals.
"The more mistakes found, the more insecure the exam system becomes," she said. "And it's insecure already."
Jerry Jarvis, managing director of Edexcel, conceded the software will alter the relationship between teachers, parents and examiners, but was adamant that transparency could only be positive.
"It's about getting integrity into the system," he said. "But there needs to be a discussion about how it is done."
Chris Montacute, head of Wootton Bassett school in Wiltshire, who took part in a pilot earlier this year, said it had helped teachers spot borderline cases where there were genuine concerns. The programme has also allowed heads to zero-in on teachers whose pupils underperformed, and helped coach pupils for re-sits, he said.
Pupils who saw their marked scripts were "fascinated to see what they did right and wrong", he added.