Q: Would you be interested in a TiddlyWiki app?
Of course and I think this is a great idea too with many opportunities, like you wrote.
Q: What would you use the app for?
Mainly for keeping track of my countless ideas and keep vital information at my fingertips. Of course there are many other apps on iOS doing the same. But over the last 15 months I got familiar with TiddlyWiki and it’s versatile configuration that I rarely use other things/apps.
I find it tempting to tinker around with TiddlyWiki whenever I have some spare time left, because I almost keep my mobile phone with me.
Oh, almost forgot that I use it heavily at work to gather all sort of valuable information (small projects, contacts, meetings, how-to’s, ticket-tracking, etc.) - never could stay alive without it!
That’s way I’m really keen on having a full working TiddlyWiki instance on my mobile - we are moving towards Windows11 at the office and there will be several security measures, too. Like allowing execution for certain registered apps (all others will be blocked, therefore no local webDAV server), encrypted USB devices only (no decryption outside the office environment means no data transfer to and from private devices) and potentially no custom PlugIns for Web Browsers (means no use of Pmario’s “file backup plugin” ).
Q: How much would you pay per year/month for a TiddlyWiki application that works on all your devices?
I hate software subscriptions in general, because costs tend to pile up. I bought several apps in the past, most of them were one-time-payment. I don’t like to pay for ALL of them in a subscription model.
But for a TiddlyWiki App I would change my mind - why?
It’s finally a good opportunity to spend you some money for your great concept and your many ideas and continous hard work.
15 to 20 pounds per month would be fine for me.
Q: What areas of functionality are important to you?
I’m actually using Quine2 and a webDAV server at home. Along with “Filebrowser Professional” (www.stratospherix.com) and a custom user sync (which runs periodically in the background) I can keep all of my (single-file) Wikis up to date on all of my devices. Filebrowser Pro was a one-time payment and is well worth the money.
As long as the iOS app keeps up with the same functionality like single-file Wikis, this would be fine for me. Sync would be done with Filebrowser Professional.
But I’d also like to evolve, using MultiWiki-Server and node.js TiddlyWiki - so yes, if I could get this additional functionality it would be very nice, too.
What I don’t like is being pushed to use cloud services. As an option, this would be alright, but I also need a chance to keep my data local.
Q: What apps do you already pay for? What makes them good value for money?
Filebrowser Professional (tons of options, the perfect file manager on iOS). Quine2, to run TiddlyWiki on my Apple device.
Most of my app purchases were done to get rid of the annoying ads 
Q: Do you prefer upfront or subscription pricing?
Subscription pricing preferred to show support for Jeremy’s work.
Q: Do you see any risks or downsides with exploring this opportunity?
In the worst case the App isn’t approved by Apple - so I think it is important that you try to approve it early.
But on the other hand I can’t see a real problem why it shouldn’t be approved.
Positive thinking!
Looking forward for a first test with Testflight - where can I sign in? 
