Oh dear, I had the exact same idea near the top of my list. Glad to see it is being well received, and nicely done, too. Good speed to you! When I use the test

Oh dear, I had the exact same idea near the top of my list. Glad to see it is being well received, and nicely done, too. Good speed to you! When I use the test file, it makes all fields required. It should probably accept empty/unknown values, no? (I just saw you commented on that elsewhere) In my experience, the manual validation feature is not that useful for most use cases, where the sheets have lots of rows. My clients have always preferred to have a list of validation errors / row numbers, modify the source spreadsheet itself using all the power of Excel, and reupload. I think the true value of this tool will be in how well it deals with messy data. A common problem is character encoding. At the moment, when I put in Polish characters in the file "EACĄŚŽĄĘĆĄ", it gets displayed as "EACĄŚŽĄĘĆĄ" - need to fix that. The validation could be more robust. Common data types (age, first names) could easily have their own specific rules. At the moment, you can put negative or out of range values for the age, or special characters for the name. And what would be really valuable is detection of outlier values - to tell the user if a value is three times longer than other values in the same column, contains unusual characters, etc. As for features, I would like a PDF import (you can just take one of the open source pdf2excel libraries, then write a bit of smart code to detect&strip the headers and footers - took me 3 days to implement last time and the client loved it ;) Doesn't need to cover all cases to be very useful. And of course, file upload is a must, ideally allowing multiple columns IMAGE1, IMAGE2, etc.