eFile could be free too but it's an enormous pain in the ass to even get registered as an IRS developer. IRS provides docs: https://www.irs.gov/e-file-provider

eFile could be free too but it's an enormous pain in the ass to even get registered as an IRS developer. IRS provides docs: https://www.irs.gov/e-file-providers/tax-year-2021-modernized-e-file-schemas-and-business-rules-for-individual-tax-returns-and-extensions https://www.irs.gov/e-file-providers/tax-year-2021-modernize... but hides them from the public.