Not to be excessively negative, but this really means very little without more context. Maybe it was very slow before, or it's a particulary unused scenario. I'm always skeptical when people write such praises of their own software without giving a comparison point.
That is at least partly the case. I maintain msgspec[1], another Python JSON validation library. Pydantic V1 was ~100x slower at encoding/decoding/validating JSON than msgspec, which was more a testament to Pydantic's performance issues than msgspec's speed. Pydantic V2 is definitely faster than V1, but it's still ~10x slower than msgspec, and up to 2x slower than other pure-python implementations like mashumaro.
Eeh come on, I think it's a bit unfair to compare, because msgspec doesn't support regular python union types… which are the number 1 source of slowness… at least in my real world use case of the thing. I've got hundreds of classes with abundant nesting and unions.
In pydantic v2 they did the same thing i've been doing in typedload for a few versions already: check the field annotated with a Literal and directly pick the correct type, rather than do try and error. So now the speed for unions has become better.
Even so, for being binary vs pure python, I'd have expected much more.
Pydantic was a pure python library and was rewritten in Rust recently. To be fair, I have seen some critiques of this rewrite. Specifically saying that the validation model could have been much faster in Python and switching languages papers over the deficiencies. I'm not in a good place to judge if this is true or not.
I wrote so in other comments… I was surprised to see that for the benchmarks of my library (typedload), it now manages to win a few… but not all of them.
I re-do the benchmarks of typedload when I make a release. The benchmarks will be updated when the next release happens.
I will not do a new release because you need new benchmarks after 3 days. You are free to include benchmarks on your own website (but we both know you won't do that).
This is because of how my whole setup works, requiring a git tag and a finished CHANGELOG. Running the command to regenerate the website would cause documentation from the master branch to be published.
I maintain typedload (a similar project, that I started before pydantic's first release) and pydantic 2 somehow still manages to be slower than a pure python library that got no funding to improve performances.
