What happens to the file you upload

You are being asked to upload a record of everything you have bought and sold. That is about as personal as a document gets, and "trust us" is not an answer. So here is what the code actually does, and every claim on this page is checkable by reading the source.

It is never written to a database

Your statement is held in the server's memory and nowhere else. Not in Postgres, not on disk, not in a log file. This matters because deleting a row from a database does not really delete it: there are backups, replicas and write-ahead logs, and a promise to delete is only as good as all of them. A promise that it was never written down is one you can verify by reading one file.

It is deleted in 2 hours, or the moment you ask

There is a delete button on the results page. It removes the entry immediately. If you close the tab and forget, it expires on its own and becomes unreachable at that instant rather than whenever some cleanup job next runs.

There is no account, so there is nothing to link it to

No email, no password, no signup. You get one cookie holding a random 256-bit identifier, which is how the results page finds your upload again. It is not a name, a counter, or a hash of your file, and it means nothing once the session is gone.

What is counted

How many uploads parsed, which broker formats were involved, and how many breaks of each kind were found. That is it: counts by category. No symbols, no quantities, no dates, no filenames, no account numbers, nothing that could be joined back to a person or a holding. The counters exist to answer "does this find real errors", which is a question about how many, not about whose.

What basis never asks for

Your broker login. There is no OAuth, no bank connection, no read-only key. basis reads files you already have. It cannot see your account and cannot place a trade, because it has no way to reach your broker at all.

If you would rather not upload anything

Don't. The same tool runs on your own machine over your own Postgres, and the web version exists only because installing a JDK is a lot to ask of somebody who just wants to know whether their cost basis is wrong. The command line version sends nothing anywhere.