Teachers upload a scan or photo of one student's handwritten maths paper alongside the mark scheme they are marking against, and roughly two minutes later the paper comes back marked question by question. Each question shows a mark and the reasoning behind it — method marks, accuracy marks and follow-through — with each mark named against the line of the scheme it was awarded under. The teacher reviews the result, changes anything they disagree with, and decides when marks and feedback reach students. Nothing is released until they approve it.

It works with KS3, GCSE and A-Level maths, and accepts AQA, Edexcel and OCR mark schemes as well as schemes a department has written itself. Past papers, mocks, topic tests, homework and end-of-unit checks all go through the same way, one paper or a whole class set at a time. Questions the system is least confident about are flagged so teachers know where to look first, and repeated misconceptions across a set are pulled out to inform reteaching.

Schools can start with a free allowance of ten papers a month with no card required, or run a two-week departmental pilot. The vendor states that data stays in the UK.