Join Tom Zurkan and Kody O’Connell from Optimizely’s Engineering and Developer Relations teams to learn about the developer experience for the iOS and Android SDKs. In this webinar, you’ll learn: - How feature flagging sets a strong foundation for app development - How the iOS and Android SDKs work - What to expect when implementing and maintaining Full Stack in your app - The steps to create feature flags and experiments in your app - How to get started for free with Optimizely Rollouts

1. 1
How to feature flag and
run experiments in iOS
and Android
Kody O’Connell
Developer Advocate
Optimizely
Tom Zurkan
Senior Software Engineer
Optimizely

2. 2
Optimizely Introductions
Perri Bronson
Product Marketing
Tom Zurkan
Sr. Software Engineer
Kody O’Connell
Developer Advocate
https://twitter.com/pezbronson https://twitter.com/KodyOConnellhttps://medium.com/@TomZurkan

3. 3
Housekeeping ● We are recording this webinar
● You will be emailed the slides and
recording
● Ask your questions via the webinar
questions box
● We’ll answer all questions at end

4. 4
Agenda
1. Why use feature flags in mobile app development? (Kody)
2. How the iOS and Android SDKs work (Tom)
3. The steps to create free Optimizely feature flags in your iOS app (Kody)
4. How to set up a feature experiment with Full Stack (Kody)
5. Q&A (Tom and Kody)

5. 5
What are feature flags?

6. Feature Flags
if feature_flag is ‘on’:
do_something()
else:
do_something_else()

7. 7
Controlled Rollouts
100% ROLLOUTGRADUAL
ROLLOUTBETA USERSSTAGING
ENVIRONMENT
LOCAL
DEVELOPMENT

8. 8
How do Feature Flags
fit into CI/CD?

9. 9
Software Development Life Cycle
DEPLOY
BUILD &
TEST
RELEASE
Develop & Iterate Quickly
● Selectively enable test suites
and making data-driven
technical evaluations
● Don’t waste time untangling
messy merge conflicts
Delight Your Customers
● Empower teams to
manage their own releases
● Incident? Minimize time to
solution
Scale Feature Delivery
● Ship faster by decoupling
deploys from releases to
shorten development cycles
● Deploy frequently and safely

10. 10
Faster Development Cycles
Features don’t need to be complete to get merged
● No stale feature branches
● Smaller code reviews
● Safety of a feature flag
BUILD & TEST

11. 11
Seamless Delivery
● Decouple deployment from release
● Stop worrying about when to deploy
● Deploy freeze != Feature freeze
○ E.g. Thanksgiving Weekend
DEPLOY

12. 12
Feature Control
● Empower teams to manage their own
releases
● Test out your feature on a small targeted
audience 🐥
○ Easily manage beta customers
RELEASE

13. 13
Incident Response
It’s 3am, you get paged… 😱
● Smaller changeset → easier investigation
● Roll back, don’t hotfix
● Someone else having an outage? → killswitch
● Don’t roll back an entire version for a single bug
RELEASE

14. 14
Feature Flags on Mobile

15. Feature Flags
on Mobile

16. mobile_app_header
Feature Flags
on Mobile

17. mobile_app_header
search_ranking_algorithm
Feature Flags
on Mobile

18. mobile_app_header
checkout_flow
search_ranking_algorithm
Feature Flags
on Mobile

19. 19
Beyond Feature Flagging:
Experimentation

20. mobile_app_header
checkout_flow
search_ranking_algorithm
Feature Experiment
on Mobile

21. enabled: True
header_color: #F829EA
header_sticky: True
header_height: 20
mobile_app_header
enabled: True
checkout_version: 3
quick_checkout: True
header_height: 20
checkout_flow
enabled: True
fresh_boost: 1.25
profile_boost: 2.10
local_boost: 0.75
search_ranking_algorithm
Feature Experiments

22. Remote
Configuration
enabled: True
header_color: #F829EA
header_sticky: True
header_height: 20
mobile_app_header
header_message: ‘We
love our users <3’
We love our users <3
SDK polls for new config at
desired frequency
Webhooks deliver new
config in seconds

23. 23
Sounds great, but how does it work?

24. How Optimizely Full Stack Works
JSON
Datafile
Client SDKs
Server SDKs
Remote
Config
Data
Warehouse
Remotely configure
flags / experiments in Optimizely.
(UI and/or REST API)
Update the JSON datafile
SDKs make decisions locally,
track events asynchronously
for zero latency
Analyze results through
Optimizely and/or exports
and integrations into your
other systems
Optimizely
Event Tracking
Event Tracking

25. How iOS/tvOS SDK works
Client - Interact directly with the client
DatafileHandler - Responsible for getting, polling and caching datafile
EventHandler - Saves and sends events to Optimizely backend
UPS - User Profile Service holds previous bucketing information

26. Unique to iOS/tvOS SDK
- Written in Swift with safety first and modern APIs
- No core data (we use file for events by default).
- Event handler has event batching for performance.
- Datafile handler and event handler are unscheduled when
app goes to background.
- Clean Swift API with Objective-C hanging off to the side.
- Take a look at my medium articles on the Swift SDK
design (enums, atomic property, dependency injection,
and exposing Objective-C API)

27. How the Android SDK works
Manager - Holds the Optimizely instance from the Optimizely Java SDK
DatafileHandler - Implements ProjectConfigManager. Responsible for getting,
polling and caching datafile
EventHandler - Saves and sends events to Optimizely backend
UPS - User Profile Service holds previous bucketing information

28. Unique to Android SDK
- Datafile handler uses the intents and the JobScheduler to
schedule future updates even in the background
- Events are also uses intents and the scheduler to
schedule attempts at flushing the events.
- Events can be triggered to send after a connection
becomes available.

29. - Android and iOS features will converge.
- Config diffs instead of full configs.
- IDE Plugins to help with development
(https://plugins.jetbrains.com/plugin/13969-optimizely)
What’s next for our mobile SDKs

30. 30
Let’s create a feature flag and set up
an experiment in Swift.

31. 31
Best Practices
Visibility
● Flag On or Off
● Environment Deployed
● Behavior of flag ON/OFF
Risk Assessment
● Can this feature be
rolled back safely?
● What happens if this
flag were to fail?
Exit Criteria/Expiration
● When is the usefulness
of this flag over?
● How soon should we
remove this flag when it
is no longer needed?
● Who should be
removing this flag?
Communication
● Who should be alerted
when flag is turned ON?
● Who should be
monitoring metrics?
● Who should be alerted if
flag is turned OFF?

32. 32
Resources
iOS
● Swift SDK and demo app on Github https://github.com/optimizely/swift-sdk
● Swift SDK docs https://docs.developers.optimizely.com/full-stack/docs/swift-sdk
● Kody’s blog post https://blog.optimizely.com/2020/02/24/feature-flags-swift-ios/
Android
● Android SDK and demo app on Github https://github.com/optimizely/android-sdk
● Android SDK docs https://docs.developers.optimizely.com/rollouts/docs/android
General
● Optimizely Full Stack product info https://www.optimizely.com/platform/full-stack/
● Optimizely SDK IntelliJ plug-in https://plugins.jetbrains.com/plugin/13969-optimizely
● Tom’s Blog https://medium.com/@TomZurkan

33. optimize.ly/mobile-rollouts
Free feature flags & controlled rollouts

34. 34
Questions?