Apple Swift Blog
The official Apple Swift Blog contains articles about Swift features.
objc.io Blog
The guys at objc.io have not only great articles, workshops, books and a vidcast, they also have a great blog.
NSBlog
Mike Ash's Friday Q&A is one of the best resources of low-level technical information for Mac and iOS development.
Swift Weekly Brief
An awesome weekly newsletter about news about the open source Swift implementation.
NSHipster
NSHipster is a top-notch journal aiming to document those secret gems in Apple's development frameworks.
Cocoa With Love
Matt Gallagher has one of the most active and interesting Cocoa-related blogs these days.
Cocoa Is My Girlfriend
A great resource, Cocoa Is My Girlfriend features blog posts by different authors, all about Cocoa-development.
Hamster Emporium
Greg Parker is one of the most knowledgable people about low-level ObjC runtime stuff and he shares his wisdom on his blog.
Big Nerd Ranch
Greg Parker is one of the most knowledgable people about low-level ObjC runtime stuff and he shares his wisdom on his blog.
Nat!'s Journal
Nat!'s Journal at Mulle kybernetiK contains a lot of technical knowledge including low-level runtime stuff.
Rentzsch
The blog of Wolf Rentzsch of mogenerator and mach_inject fame.
Ridiculous Fish
Ridiculous Fish of Hex Fiend fame has a great blog mixing insights into physics, mathematics, low-level hacking and much more.
Indie Stack
Daiel Jalkut hacks the Mac, iOS and more for us at his blog.
Erica Sadun
Erica Sadun of Swift.org fame has an insightful Swift-related blog.
Russ Bishop
Russ Bishop is an Apple Engineer and blogs about Objective-C and Swift stuff.
Call Me Fishmeal
Wil Shipley's blog on Apple-development and Fishmeal.
Andyy Hope
Andyy Hope from down-under has a great Swift-related blog.
Metablog
Marcel Weiher of Objective-Smalltalk and MPWFoundation fame has a great blog. He also writes great books.
Cocoa Samurai
Colin Wheeler is Cocoa Developer & Enthusiast working on Mac & iOS apps and blogs like a Samurai.
Desolation of Blog
Jeff Johnson's blog features notes of interest for Objective-C and Swift developers.
Weaponized Fluff
Andrew Pontious's blog talks mostly, but not always, about developing for Apple devices.
Peter Steinberger
Peter Steinberger's blog is mostly about iOS development.
NSProgrammer
The name says it all - sadly Nolan O'Brian's blog hasn't been updated since 2013.
Fun with Objective-C
This was fun while it lasted, but hasn't been updated since 2011.
Theocacao
Scott Stevenson's Theocacao has once been among the top Cocoa blogs, but hasn't been updated since 2009.
Medium.com Swift Programming
A meta-blog collection of articles from blogs on Swift programming.