The best replacement for interface builder is programmatically.

The best alternatives to interface builder are rated as following:
★★★★★  programmatically
★★★★★  storyboard
★★★  xcode

Your alternative for interface builder is not listed? Suggest!
Speaking about interface builder, one probably shouldn't forget about cocos2d.

Other search terms related to interface builder and their ratings are:
★★★★★ cocos2d
★★★ applescript
★★ cocoa
You have in mind a companion for interface builder and it is not yet here? Propose!



Google Trends

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interface builder
programmatically
storyboard