Presented to Silicon Valley iOS Developers meetup group Nov 18, 2014. Hosted at Coursera in Mountain View, CA. Notes: As you know, Coursera is a leader in online education with nearly a thousand online courses that you can watch on an iPad (and more). They've promised something interesting to share with us Monday as well: a look “Under the Hood of Scalable Apps” by iOS engineer Brandon Tram and Android engineer Michelle Wong. Thanks also to Paul Robinson and Saul Mora at Coursera for agreeing to host us!

1. Under the Hood of
Scalable Apps
Brandon Tram (btram@coursera.org)
Michelle Wong (mwong@coursera.org)

2. • University of Waterloo
• Co-op program
• Mobile - iOS & Android

3. Universal Access to the World’s Best Education

5. Mobile @ Coursera

6. Coursera iOS 1.0
What about
scaling up?
Forget scale
SHIP IT

7. Scaling up How do we
measure growth?
What about
adding X & Y?
This legacy code
is not so great…
Test? Test? Test?

8. New Methodologies
“86% of time is spent using apps, 14% is spent browsing”

9. Feature Modules
What about integrating large features?

12. Coursera Debug Tools

14. Activating Tweaks
• Employee verification
• Volume key
• Overlay icon
• Secret gesture

15. Tweaks: Other Examples
• Client-side
• FB Tweaks
• Remote
• GroundControl
• Rollout.io

16. Tweaks Challenges
• Defining a useable interface
• Activation method
• Changing app state at runtime

17. How do we
measure growth?

18. Analytics Lifecycle
Product Team Partners
Eventing
Platform
Analytics
Team

19. Event: pause_clicked
Properties:
- video id
- video time
- play back rate
- subtitle language
- volume
Metadata:
- timestamp
- app version
- os version
- etc

21. Mobile Metrics
• 26% of all video views
• 6.5 million views
iOS Android Web
60%
26%
14%

22. Debug X-Ray
• Event key, metadata filtering
• Send to email, Google Drive
• Tweaks-enabled

23. Dispatch Sources

24. Dispatch Sources

25. Analytics Challenges

26. Takeaways
• You have a great app in production or market
• Scale team: feature flagging
• Scale user growth: accurate analytics tracking

28. Thank You!
btram@coursera.org
mwong@coursera.org