New Go API for JSON
The gist
The Go team released encoding/json/v2 and jsontext as stable in Go 1.27 after about 6 years.
Unmarshal runs up to 10x faster, but v2 rejects inputs the old package accepted.
How it unfolded
- Aug 2, 2026Go 1.27 is reported to include encoding/json/v2, experimental since Go 1.25, available without a build flag, with classic encoding/json now backed by the v2 implementation.
- Aug 19, 2026Go 1.27 is released with encoding/json/v2 and encoding/json/jsontext; the new packages reject invalid UTF-8 and duplicate object member names.
- Nov 4, 2026The Go team publishes a blog post announcing the packages are stable and generally available in Go 1.27.