IELTS GROUP PREP
A study app for a group preparing for IELTS together, built around daily tasks, mock scores, an error log and an automated writing feedback tool.
A mock score says how someone did, not what to practise next. And a free writing-feedback tool that costs money for each check can run up a bill if anyone can press the button.
The app is organised around turning a result into the next action. Alongside a twelve-week plan, daily tasks, vocabulary, mock tests and group sessions, an error log records the reason behind each mistake, so the group can see what to work on.
It began as a single-device app and moved to shared accounts the same evening, so a group could use it across devices. Later passes guarded daily logs and streaks against overwrites from two devices at once, and corrected the wording so the band tables are no longer called official.
The public automated writing feedback has a quota: three checks per visitor and fifty overall in any 24 hours. If the tool can't read how much has been used, it refuses rather than guessing, because the cost of guessing wrong is an open-ended bill. It reserves a slot before the paid check runs, and stores visitor addresses only as salted hashes.
The limit: the band shown is an estimate, not an official examiner score. Checking the quota and reserving a slot are two separate steps, so two requests at the same moment could both get through.
Next I would make the quota check and the reservation a single step, test it with many parallel requests, and compare the automated feedback against examiner-marked samples before showing a band at all.