Error on deploy: No JSON object could be decoded

I am trying to deploy a project I could previously deploy on Kobotoolbox from a xlsx upload. The file uploads correctly, but when I click “deploy”, I get this message: “No JSON object could be decoded”. Unlike other incidents I have seen documented, this is happening with the version open to “Researchers, Aid Workers, and Everyone Else”, so I cannot utilize the workarounds recommended for self-deployed kobotoolbox installations.

SOLVED! It appears that some of the regular expressions I used for constraints in the forms are no longer supported, but the validation only fails when processing the XForm XML derived from the XLS. I was able to debug my form using this tool:


Thanks i tried your way and it worked out for me, thanks a lot

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Hi, I’ve been having the same issue but only with one of my .xls forms. Yesterday I was able to upload and deploy a similar .xls form with no issues at all, so I don’t understand why this particular form is not working. I tried to use the tool recommended but the form that doesn’t work seems to have the same issues on that tool as the form that does work. Is this JSON error always due to constraint expressions?

Any advice at all would be very much appreciated!

For anyone else that has this issue - this error can also be caused if variables are not encoded properly - e.g. if a variable is referred to as “variable” instead of “${variable}”


Hi @epigridel,

Welcome to the community! Thank you for sharing your experience and knowledge with the entire community!

Have a great day!