The current cross-versions winner is usjon 🎉
@@ Python 3.13.1 @@
! json……………… loads: 5.816 x1.0 | dumps: 8.162 x1.0
- ujson…………… loads: 7.314 x1.3 | dumps: 6.905 x0.8
- fast_json… loads: 7.338 x1.3 | dumps: 9.165 x1.1
- rapidjson… loads: 9.276 x1.6 | dumps: 7.219 x0.9
- pyjson5……… loads: 9.861 x1.7 | dumps: 8.017 x1.0
- simplejson loads: 6.645 x1.1 | dumps: 17.459 x2.1@@ Python 3.12.8 @@
! json……………… loads: 5.864 x1.0 | dumps: 7.838 x1.0
- ujson…………… loads: 7.435 x1.3 | dumps: 6.804 x0.9
- fast_json… loads: 7.343 x1.3 | dumps: 8.649 x1.1
- rapidjson… loads: 8.799 x1.5 | dumps: 6.946 x0.9
- pyjson5……… loads: 8.983 x1.5 | dumps: 7.813 x1.0
- simplejson loads: 7.285 x1.2 | dumps: 17.637 x2.3
- simdjson…… loads: -.--- x-.- | dumps: 7.676 x1.0@@ Python 3.11.9 @@
! json……………… loads: 5.914 x1.0 | dumps: 8.889 x1.0
- ujson…………… loads: 7.011 x1.2 | dumps: 6.519 x0.7
- pyjson5……… loads: 8.398 x1.4 | dumps: 7.045 x0.8
- fast_json… loads: 6.922 x1.2 | dumps: 9.406 x1.1
- rapidjson… loads: 8.379 x1.4 | dumps: 7.841 x0.9
- simplejson loads: 6.207 x1.0 | dumps: 16.493 x1.9
- simdjson…… loads: -.--- x-.- | dumps: 8.605 x1.0@@ Python 3.10.11 @@
! json……………… loads: 6.089 x1.0 | dumps: 8.893 x1.0
- ujson…………… loads: 7.036 x1.2 | dumps: 6.593 x0.7
- pyjson5……… loads: 8.503 x1.4 | dumps: 7.410 x0.8
- rapidjson… loads: 8.592 x1.4 | dumps: 7.392 x0.8
- fast_json… loads: 6.970 x1.1 | dumps: 10.110 x1.1
- simplejson loads: 7.100 x1.2 | dumps: 16.524 x1.9
- simdjson…… loads: -.--- x-.- | dumps: 9.071 x1.0@@ Python 3.9.13 @@
! json……………… loads: 6.363 x1.0 | dumps: 8.697 x1.0
- ujson…………… loads: 7.037 x1.1 | dumps: 6.679 x0.8
- rapidjson… loads: 8.851 x1.4 | dumps: 6.781 x0.8
- fast_json… loads: 7.075 x1.1 | dumps: 10.093 x1.2
- pyjson5……… loads: 9.191 x1.4 | dumps: 7.294 x0.8
- simplejson loads: 7.437 x1.2 | dumps: 14.090 x1.6
- simdjson…… loads: -.--- x-.- | dumps: 8.999 x1.0