Is this advanced? If you have ever or will ever attempt to implement an idiomatic encoder/decoder in Go, you will learn everything this post talks about.
I use it here because most introductory posts about encoding/decoding in go (like https://blog.golang.org/json-and-go) don't touch on these at all. Instead many people figure each of these out separately over time.
On a positive note, it does look like it's well written. Detailed with clear examples and laid out in a clean design that's easy to follow.