The app industry is growing more competitive every year. As of September 2014, there are 1.3 million apps on the App Store and only 16% of people will try your app more than twice. I spend most of my time in the San Francisco Bay Area talking with app publishers about where they are in their product cycle and how we can help them improve user engagement with mobile location. In these conversations, I’ve come to know which SDKs are valuable to certain parts of building and growing an app. The five SDK categories below are the ones I hear about most often and in each category I’ve named several specific SDKs that are loved by app publishers, and which not.

1. Crash reporting

2. Analytics

3. A/B Testing

4. In-App Feedback & Rating

5. User Engagement

Crash reporting

It’s common for new apps to deal with crashes and bugs. Crashes and bugs lead to low app store ratings, fewer installs, and a drop in active users. Eduardo Iglesias, CTO at Tutton, told me his team uses Instabug to fix these issues. “Instabug is great because it permits us not only to track crashes, but to track bugs that happened in our apps, and try to solve them. The SDK give us the ability to send a photo, with the email and a message from the user.” Crittercism is another great SDK for tracking crashes. When one occurs, they send you an email with log files so you can figure out why a crash occurred.

Analytics

Your users will likely take actions in your app that you didn’t anticipate, or they could be getting stuck or dropping out of the app on certain pages. There are analytics tools that identify these pain points and opportunities in user actions. Solutions range from collecting basic data relating to mobile app usage, to more sophisticated solutions that track specific and detailed aspects of user behavior. Max Alexander, Founder at Epoque uses Mixpanel. “Mixpanel is the simplest way for me to track what users do in my app. It has a very simple user setup process which threw the burden of complexity out the window.” Mixpanel is an excellent solution for small and medium data volumes.

The one SDK that every app developer I speak with talks about is Google Analytics. It provides traditional analytics and focus on key metrics such as number of users, OS versions, geographic breakdown, session length, etc. But, if you want to dive into the user behavior and user experience, their solution won’t tell the the full story, since they emphasize the what instead of the why. For example, you may detect that you have a low user retention, but you won’t understand why users are not returning to use your app. The Localytics Analytics platform has user analytics, segmentation, engagement analysis and lifetime value tracking. It is also useful for push notification and in-app messaging management.

A/B Testing

Once you’re as close to 100% crash-free as possible and you know what users value in your app, it’s smart to test UX variants to create a better experience for users. The problem is that it’s time-consuming to submit a release to the app store only to find another necessary change that will have to wait 8-10 days for approval. Taplytics allows rapid iteration and improvement by A/B testing small UX changes in your app without submitting to the app store. The user insights and segments let you see the actions users are taking within the app so you can make informed changes to improve your app’s experience.

In-App Feedback & Rating

The app store is competitive. Five star reviews sends a powerful signal to new users that they will have an exceptional experience on your app. How many times have you seen a one star review start by saying “one star for prompting me to review their app?” Apptentive helps you get five star reviews on the app store by asking users to rate your app at the right time.

User Engagement

Once you’ve worked out bugs and solidified the core features of your app, it makes sense to focus on user engagement with app messaging. “I forgot” was the #1 reason one well-known app with a 4.5 star average review hadn’t been opened by its users in the preceding 28 days. AppBoy makes it easy to deploy engagement campaigns with push notifications and email and they produce tools to test what works best with different user segments. Also, my company, Hangit, enables apps to send their users contextually relevant messages – personalized and targeted to each user at an exact time and place. User location is highly correlated with relevance, so whether yours is a video app, a grocery list app, a messaging app, or something else, there are likely many compelling use cases for location-driven notifications.

The app development process is dynamic. Gathering data on crashes and bugs should be a priority with your new app, and as you gain momentum, it will be important to engage and grow active users and (hopefully) monetize. Good luck!