I don't have experience with BPMN/BPML but I'd still be interested in helping out if you get something started. I'd recommend targeting the folks with relative

I don't have experience with BPMN/BPML but I'd still be interested in helping out if you get something started. I'd recommend targeting the folks with relatively simple taxes (salaried/wage employees with limited and structured investments, nothing super fancy) who make more than the Free-File cutoff, and then work your way out from there. The "I own 4 businesses and have 17 different investments all structured differently with various business expenses that are different degrees of write-off-able" group isn't your target, and there's already FreeFile options for folks making poverty-level wages. The toughest part here business-wise is probably the liability - TurboTax and HR Block and whoever have armies of lawyers and PR and insurance to handle cases like a user getting audited and blaming them or catching flak for clients over-paying. Those armies are there to protect Intuit, not the end user, but they're fairly important nonetheless.