JSON v2 Lands in the Go Standard Library
Overview
The encoding/json package is one of the oldest packages in Go (golang), and it shows. It matches field names case-insensitively, silently accepts duplicate keys, and marshals nil slices as null. We've all worked around these for years. Thankfully, Go 1.27 ships the fix: encoding/json/v2 graduates from experiment to standard library. It's stricter by default, significantly faster at unmarshaling, and your existing encoding/json code keeps working. In this article, we'll walk through what actually changes, by example.