Productive tools for iOS app development
Xcode is one of the best IDE for coding, so we can’t do anything without that. But there are better tools for other cases especially debugging of UI/Network layer. I highlighted specific features which might work for you as well. If you are interested for more details, try out free version at first.
Reveal
Reveal is a runtime view debugging tool.
With advanced visualisations, comprehensive inspectors and the ability to modify applications on the fly, you’ll be debugging view layout and rendering problems in seconds.
Xcode 8 also introduced view debugger, but I think Reveal is definitely better in terms of everything. In case you often use AutoLayout, it’s going to be a best fit for that case. It shows all of constraint values visually and tells you conflicts with unexpected constraints.

You can run Reveal with your actual device, nut just iOS simulator.
AppCode
AppCode is smart IDE which can be replacement for some others cases. It has so many features mostly for coding and integrations with other tools. But you have to use Xcode when you open Storyboard/Xib file.

Here is my favorite features often used.
Override/Implement
You can override/implement all of required methods by protocol you conform to at once. You can also search optional methods by camel humps.


Refactoring
AppCode lets you to refactor return type, argument type and argument name, not just method name. This might not be available for Swift, but still useful a lot.

Integration with Reveal
AppCode provides seamless integration with Reveal. Simply press Reveal button to run Reveal after you run your app. Code faster with AppCode and Debug faster with Reveal.

Paw
Paw is REST API client.
Paw is a full-featured HTTP client that lets you test the APIs you build or consume. It has a beautiful native OS X interface to compose requests, inspect server responses and generate client code out-of-the-box.
It handles authentication well, so you don’t need to copy and paste every time you call API. You can store any values as environment variables so that you can switch your host name for production/development server.

It helps a lot when you have issues with HTTP request, because it shows you all of information about HTTP request/response. Especially when you develop your client app and server API at same time, it saves so much time to debug implementation of network layer.
個人的には、PawでAPIを色々試してみて、試したリクエストを使ってテストケースを書いて、その後にアプリ側で通信処理を実装するという流れが効率が良いと思っています。
Charles
Charles is HTTP proxy tool.
Charles is an HTTP proxy / HTTP monitor / Reverse Proxy that enables a developer to view all of the HTTP and SSL / HTTPS traffic between their machine and the Internet. This includes requests, responses and the HTTP headers (which contain the cookies and caching information).
You can change HTTP response body to whatever you want. Usually debugging error case with network layer is so much pain, but it’s not going to be like that if you have Charles.

Dash
Dash is a documentation browsers.
Dash is an API Documentation Browser and Code Snippet Manager. Dash stores snippets of code and instantly searches offline documentation sets for 150+ APIs (for a full list, see below). You can even generate your own docsets or request docsets to be included.
Of course, there are iOS/Swift documentations. Other than that, you can find some documentations of open source library available through CocoaPods.

Recap
These productive tools save so much time, so that you could focus on coding more efficiently. I really recommend to use these tools to develop better apps!
