Learn

One subject, split across several parts, followed all the way down. Each series is a curriculum: read it through and you end up able to build the thing yourself.

What goes in here
The shipped bundles of five embeddable JavaScript SDKs, fetched and read line by line. What I ran and verified myself is marked apart from what I only assessed from the vendor's own documentation, and chapter 0 of each series says which is which.
Reading order
Start at chapter 0. It carries the comparison table and a list of what each chapter covers. After that, jump to the chapter you care about or read straight through. Order only matters for chapter 0.
How this differs from the blog
The blog is one post, one subject, done. This section takes the subjects that will not fit in one post. Comparing five SDK designs needs a chapter per design; compressed into one post, every one of them stays at the surface.

Series

1 series / 2 chapters

More series, and more chapters per series, are published in Japanese at kenimoto.dev/ja/learn.