Disclosure: I work on Fancy Product Designer (Chamevo).
Since you’re printing in-house, you want an app that generates print-ready files rather than routing to a third-party POD provider. FPD is designed for exactly this use case – customers customize on the storefront, and you receive print-ready output files with proper CMYK color profiles in the order.
The workflow: customer designs their shirt on your site → places order → you download the print-ready file → send to your printer. It supports DTG, DTF, screen printing, and sublimation output.
The majority of our merchants actually run their own production – no POD provider lock-in. $30/mo with 14-day trial.