sync.Map has changed since my previous sync.Map article. Its public API stayed the same, but Go 1.24 changed its default implementation to an experimental hash trie.

Go 1.26 removed the experiment flag and made the hash trie the official implementation of sync.Map in the standard library.

We will discuss the current implementation from the beginning, so you do not need to read the old article first. We will build everything up from a normal map to the design behind sync.Map. If you already know the setup, feel free to skip those sections.