[jackqu7]

(I'm Jack, another developer at OSL.)

We started writing Kim around the same time as the Marshmallow project began as we found it wasn't suitable for our needs at that time, though it has come a long way since then.

They are very similar projects and have similar functionality, but Kim has a focus on making it relatively simple to do unusual or 'advanced' things.

For example, Kim supports polymorphism out of the box, if you have an AnimalMapper subclassed by a CatMapper and a DogMapper, passing a Cat and a Dog to AnimalMapper.many.serialize() will automatically do the right thing in a similar way to SQLAlchemy polymorphism.

We also have support for complex requirements such as nesting the same object to itself (useful when your JSON representation is nested but your DB representation is flat,) serialising multiple object fields to a single JSON field (eg full_name consisting of obj.first_name and obj.last_name,) a range of security models for marshalling nested objects and a fairly extensible roles system.

In general we've followed the philosophy "Simple things should be simple. Complex things should be possible."

[bpicolo]

I've been saddened by Marshmallow on many occasions (I have gripes with the particular way defaults/validation play together. This is true for WTForms too).

I'm excited to try out Kim. I've been very close to just writing my own serialization lib on many occasions.

It looks like your pipelines might bring a bit of sanity to it. :)

It looks like you support a few sorts of validation, but the docs aren't super clear as to what the expected validation strategy is. Could you elaborate on what that looks like?

My typical strategy I'd like to do is to just a list of functions that take the input and return a boolean as far as validation goes.

[mikeywaites]

Hey that's really great to hear. (that you're keen to use Kim) WTF-Forms and Marshmallow both solve problems and they do it well but it seems like us you wanted something that offered just a bit more flexibility. That's totally the idea behind pipelines in Kim. They are like tiny little computer programmes and are really capable of anything (providing it's possible in Python of course :D )

It's great you asked this question as we noticed part of the documentation was actually broken. here's a link to a pretty basic example of adding extra validation "pipes" to a pipeline

http://kim.readthedocs.io/en/latest/user/advanced.html#custo...

We'd be more than happy to discuss how to solve more complex requirements if there's something specific you had in mind though.

Thanks for the message!