Is a way to re-post the submissions that failed to POST?

I POST my submissions to a custom web application I designed. My endpoint was unavailable for a few days and I'm wondering if there is a way to re-post the submissions that failed to POST?

I'm not sure, but it might be possible with PHP. You may check Jotform's available APIs and see if it allows you to re POST failed data. You'll probably need to store those failed POST somewhere else (database) so you can write your own script to resend those.

I'm not an expert in backend scripting so you might want to consult developers who are familiar with this.