Is it good to use third party library inside app? Is it slowdown's the app speed?

I don't think your example is uncommon.

As for speed, you might see an effect from just one, depending on what it is, how well it integrates with the rest of your app, etc., or use five and not see any speed issue.

Why do you ask? Is there a specific worry someone warned you about? Might help if you listed those 3rd party libs.

**Note this doesn't seem to be an iOS Multitasking question...

Third-party libraries can be useful, and your proposed usage doesn’t seem out of the ordinary, but I do want to proffer two bits of advice:

• From the user’s perspective, and hence from App Review’s perspective, there is just your app. Any problems caused by third-party libraries will be ascribed to you, not to the library’s developer. Thus you need to make sure that you trust that code, because it will have a direct impact on how users view your app.

• You need a contingency plan for all third-party libraries. For example:

  • A commercial library might be dropped by the vendor, or the vendor might go bust

  • An open source library might lose its primary developer, and thus stop being maintained

  While circumstances vary, my general advice is to not take a dependency on a library unless you had access to the source and, if worst comes to worst, you’re prepared to maintain that code in the long term.

Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"