Below are the results of crude benchmarks comparing pydantic to other validation libraries.

Package Version Relative Performance Mean validation time
pydantic 1.1 43.6μs
attrs + cattrs 19.3.0 1.4x slower 59.9μs
valideer 0.4.2 1.4x slower 61.8μs
marshmallow 3.2.2 2.5x slower 107.6μs
trafaret 2.0.0 3.4x slower 148.7μs
django-rest-framework 3.10.3 12.6x slower 551.2μs
cerberus 1.3.2 26.3x slower 1146.3μs

See the benchmarks code for more details on the test case. Feel free to suggest more packages to benchmark or improve an existing one.

Benchmarks were run with Python 3.7.4 and the package versions listed above installed via pypi on Ubuntu 18.04.