Currently the API returns: Current buy stack int, current sell stack int. Estimated Sold and bought are done by fetching twice and comparing the difference.
This breaks under a large amount of situations.
On the sell side: If items are sold, and listed in the same period before the refetch they cancel each other out.
On the buy side: the sell side problem exists, but additionally cancelled buy orders are interpreted as purchases.
If actual bought/sold was returned this issue would be fixed as refetches would then be able to differentiate between added items and actual transactions regardless of the qty direction.
This could either be done via the actual number (ideal) or by caching a daily number calculated at a certain time depending on availability of the data.
Web Programmer
Unfortunately, this is technically infeasible. Completed transactions are not indexed in a per-item manner. Implementing this would require additional plumbing all the way from the bottom of the stack, which is beyond the scope of what we can do to support the API.
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