For my own "to do" lists, I've been using Google Tasks. There are interfaces to Tasks both from the Gmail page and the Calendar page. On Android I use Tasks. On iOS I use Go Tasks. They both work seamlessly with Google Tasks.
So I wondered if I could use Google Tasks for a grocery list. The presentaton is a natural list with a check-off box. Just what I needed.
But Google Tasks are specific to a single user. They aren't shareable. So began the quest.
First I found this blog post with a description of how to create your own Google App to share. It worked but the presentation was a unique web page and didn't seem to be readily presented on a mobile device.
Then I found I Sync Tasks. It simply just does what you want it to do.
You register with them using your Google account.
And tell them what Tasks list you want to share and with whom.
That's it. You can contribute $1 per month per user and make it sync more quickly. Seems well worth it.
Initially the sync was quick. Then after a while the frequency slowed down. I read the FAQ and it didn't specify the sync times. So I tweeted the author.
fastoy: @isynctasks I'm using isynctasks.de. What is the duration of the trial period? What is the sync frequency DURING and then AFTER the trial?Sign me up.
isynctasks: @fastoy 7 day trial; sync times vary, depend on multiple signals; within a minute during trial or if paid; within hours on the free plan.