Some interesting SDKs
Cross platform SDKs for iOS:
(Appcelerator Titanium vs PhoneGap: which produces better native apps? , Would you recommend Rhomobile Rhodes or Appcelerator Titanium for (non-native coding) native apps?)
- PhoneGap SDK
- Appcelerator Titanium SDK
- Corona SDK
- Rhomobile SDK
Analytics
(What is the best mobile analytics service for iOS apps and why?)
- Flurry (company)
- Mixpanel (product)
- Localytics
- Apsalar
Cloud
- Parse Platform (cloud backend)
Bug/Crash Reporting
(How do Crashlytics, Apphance, BugSense, Crittercism and TestFlight Live compare?)
- HockeyApp (http://www.hockeyapp.net/)
- Crittercism
- Apphance
- BugSense
- Hoptoad
Text Messaging/Voice/Telephony APIs
(What, if anything, separates Twilio from its competitors (46elks, Aculab Cloud, Angel, etc.)? , Is there an alternative to Twilio that allow users of your sms-sending-app to buy SMS credits directly?)
- Twilio
- Tropo
- 46elks
- Callfire
- http://blog.programmableweb.com/2012/06/19/373-telephony-apis-twilio-skype-and-tropo/
Engagement
- Socialize (http://www.getsocialize.com/)
- App Booster (http://appsfire.com/appbooster)
Mobile Commerce
- card.io SDK
- Jumio (company) SDK
Geolocation
- Geoloqi SDK
- Skyhook SDK
- Gimbal SDK by Qualcomm
Augmented Reality
(Which AR (Augmented Reality) libraries exist on Android/iPhone?)
- Junaio by Metaio
- Vuforia by Qualcomm
- Satch by Total Immersion
- Obvious Engine by Harmonypark
- Layar Player by Layar
- Wikitude
Mixed
- Seatwave SDK (http://www.seatwave.com/developer)