I am developing an email software/service similar to gmail and thunderbird, but I am wondering if it is a good idea to have a responsive design or also have apps for different devices?
With the rise of mobile phones, I don't think you can afford not to do it responsively. This is essentially because many people will want to use the web from a mobile phone. I do it and I am not particularly... how to say it... a phone person, i.e. I'll mostly keep my phone in my coat when I am in work, so I don't look at it as much as other people.
I do suggest, however, that you also make available native interfaces for the various options you have (desktop, android, iOS, etc.) because they will generally work better than HTML5. Facebook, which is arguably a master of the web, has gone this route - and I think you should, too.
First I would like to mention that you are actually bundle three questions in one – which is not such a good idea, since it's fairly unlikely you'll get all three quenstions answered in one thread:
- Is responsive design good for web based software?
- Should I develop native apps, even if my web based software has a mobild friendly / responsive design?
- Can anybody please suggest a good UI Framework?
However, I have the feeling you already answered parts of your questions yourself: first develop the web based application – and of course do go the responsive way. First things first. Then of course it would probably be a good a idea to also have the email service as a native app – at least I think it would be nice to also have an app e.g. for storing, reading and writing emails offline. But since app development can be quite demanding (i heard), do a mobile friendly/responsive version of your web service first.
To sum things up and give a straight answer to your question: Is Responsive Design good for web based software? Yes, definitely so. Or to look at it from a different angle: Can I afford to have a web based software that is difficult to use on mobile devices? Probably not.