How to add “Edit Response” link to Google Forms emails?

Question

I have a simple Google Form that collects data, and, using AppScript, sends confirmation emails to users who fill it out. After user submits the form, on confirmation, s/he

Answer 1

--edit this is now possible. See other answers.

After user submits the form, on confirmation, s/he will see a link to edit his/her response. I'd like to include that link as a part of the confirmation email

That is not possible, period.

That link is not accessible anywhere and one can't guess/construct it. But, there's some workarounds that might suit you (some suggested here that I'll re-phrase), e.g.

Send a per-populated form link and have the user re-send it. You'd need to have some kind of control field (e.g. the username), so you can know and delete/ignore his older submits. Possibly automatically via a script.

You could also develop and publish an apps-script GUI and send a link to this apps script plus a parameter that you generate where you can determine which entry you should edit. The down-side of this approach is that it's somewhat cumbersome and overkill to re-design the whole form on Apps Script. But again, it works.

At last, you could open an "Enhancement Request" on Apps Script issue tracker and wait until they and Google Spreadsheet/Forms team get together to develop a solution.