Since I started with mobile app design work 6 years ago, it has become increasingly important to validate design concepts with clients fast. Software and website design mockups have always been beneficial but even more so with mobile app design. With app design you want to reduce the amount of iterations and since mobile projects are usually smaller than web application the percentage of time you spend designing should be short. Another reason rapid design and visualisation and in some cases simulation is essential is with agile product development. In many projects the design leads the development with only one 2-week sprint and you need to lock down the designs fast.
The first tool I used was Balsamiq and I loved the simplicity. Most really good websites or apps start with simple design and low learning curve. Still today, I think Balsamiq is one of the better ways to rapidly prototype app and website layouts. It is mainly focussed on layouts and what makes Balsamiq good is the hand-drawn style of the layouts making it clear to the client or product sponsor that it is simply mockups and focus on the layouts and UI elements rather than color, style or branding. I still highly recommend Balsamiq for its simplicity, and relative low price. They offer single-user one-time pricing for less than $90 USD the last time I checked, and since it is one-time fee it is cheaper than most tools out there that charge subscription rates.
As I worked at consulting companies, they too invested in software licenses and were in a pursuit of finding the best prototyping and simulation tools to bring a competitive edge to our service offerings and set us apart from competitors. Naturally, since money is not really a deciding factor they looked at expensive tools, and what seems like the most capable tool on paper, or by feature list. They decided to partner and purchase licenses for iRise. iRise is in fact very powerful and a full featured tool and service that has by far the most capabilities of any rapid prototyping tools out there. But it is not for everyone. Not just because it is more expense, but after using it I realised that the many features and capabilities is over-engineered. It is too good in fact, and it takes the rapid out of rapid prototyping. If you are looking for the best to to build complex software simulations before development then iRise is the best. If you are looking faster, simple prototyping keep reading.
There are many startups, tools and websites in the mockups and prototyping space, and more pops up every few weeks. Some focus on rapid drag-and-drop layout mockups, other focus on simulating the interactions and flow of the apps, and some a combination of the two. On a very simple approach of simulating interactions only, another website called prototyping on paper or popapp.in let’s users draw their app or website layouts on paper, scan or take photos of the hand-drawn mockups and then make it interactive by adding interaction points and actions over the drawings. You simply drag an interaction point over a button outline and tell it which screen or drawing it should load next. very simple, very fast, and very inexpensive. Another similar approach but using designs you make (either wireframes or high-fidelity mockups) is invisionapp. Invisionapp let’s you import your designs from Sketch, Photoshop etc. as screens and you build interactivity on top of it. It is one of the better tools that is also mature and has a lot of nice features like advanced animations, smart interactions, templates for many devices and even smart watches, and they continuously improve the tools and templates. I recommend invisionapp, as it is a solid tool and service that will be around for a long time. The only thing it doesn’t have is rapid prototyping of low-fidelity drag-and-drop UI elements, and I usually need this type of design phase to quickly validate the layouts and features with a client.
That brings me to the best all-rounder tool I have been using for a couple of years now called Proto.io. Proto.io can do all 3 things you might want to do namely rapid drag-and-drop UI/UX mockups, interactions and simulations, and high-fidelity design imports and making it interactive. You can therefore start with quick wireframes, add interactivity, then move on by importing your actual high-fidelity or final graphics and simulate it as a real app or site. They also have apps on the Apple and Google app stores that you can use to showcase the prototypes on real devices, even in offline mode. But what I like the most of Proto.io is that they don’t charge you extra to invite as many as you like reviewers/clients to follow your progress, the ability to comment directly on your designs, and it notify your and your clients when a new comment is posted, or a new version is published. Some of my projects involved stakeholders across the globe and having a tool in the cloud where they can view, test and comment in their own time is very beneficial.
I guess it depends on several factors on how to choose the best tool. Duration/size of the project, type of software or website you are designing, budget, and project style. But if you want a simple, inexpensive tool that has most of the features but is not over-engineered, I recommend Proto.io.
Looking forward to comments and suggestions of other tools I have not mentioned/used.