What are some iOS SDK for developers to build awesome apps?

Kindly could you tell me what kind of app do you want to develop? If you are searching for iOS SDK for developers to develop some application, maybe you can go http://www.yunmai.com/en/ocr_sdks.html to search for what you want. There are some SDKs for you to choose. Yunmai Technology is professional for developing optical character recognition SDK and has become one of the best mobile OCR technology and application developers in the industry. Abbyy is also very good.

Make sure to know your users as well as you know you code! Gather feedback from customers and do customer development as much as possible, but also support them when something goes wrong. SupportKit(http://www.supportkit.io) will make this easier for you, it allows you speak to users of your mobile app, right from your inbox.

ASIHTTPRequest is an easy to use wrapper around the CFNetwork API that makes some of the more tedious aspects of communicating with web servers easier. https://github.com/pokeb/asi-http-request

I've built a free iOS SDK that's picking up a lot of steam, it's called SupportKit - http://www.supportkit.io Its a free way for you to be able to see and speak to users in your app and only takes a single line of code to integrate. Check it out next time you're building an app and want to be able to get in touch with your users to provide support, collect feedback and do customer development.

If you are looking for an API for communication on mobile, I would like to mention C2Call SDK. It's a cross-app communication tool which provides Group Video Chat, Voice Conferencing, Personal US Number, Caller-ID, CallMe-Link, Texts/SMS and Rich Media messaging such as photo, video & location sharing. C2Call has officially launched its SDK in public beta and have made it completely free of charge for app developers. The SDK can be downloaded from the official website http://www.c2call.com

Not necessarily considering this an SDK, but http://cocoacontrols.com has a lot of stuff to make your life easier!

UPDATE: We've just dropped prices in more countries! We just announced a major price reduction and more direct routes to major international countries! Get all the details here: https://www.plivo.com/blog/price-drop-with-more-direct-routes-to-carriers/ You can also check out all of Plivo's international coverage here: https://www.plivo.com/international-coverage/ And if you need more convincing, check out our Twilio alternative page https://plivo.com/twilio-alternative/  for the complete comparison. === Plivo has an iOS SDK that lets you send SMS to 226 countries, and make calls to 208 countries. Lots of developers have built apps on Plivo including, conferencing, voicemail, two-factor authentication, call centers, SMS messaging, voice call apps, just to name a few. You can sign up for a free trial here: https://manage.plivo.com/accounts/register/

I work for TalkBox and we've just launched our http://talkboxapp.com/sdk SDK which enables simple in-app voice chat (PTT) for your app. Developers should check it out!

If your mobile app needs to be awesome your app support needs to be exemplary. http://helpstack.io is an open source SDK for providing in-app customer support for mobile users. The solution is available for both iOS and Android platforms.