Transformations is something we haven't built yet but we have our eyes on it as your are not the first one to bring that up. You can use Hookdeck in front of lamda and to the transformation there, you'd still get the benefit of async processing, retries, etc
Do you have an idea of when hookdeck will have transformations. It's not something we need immediately but would be the win over something like: https://webhookrelay.com/ if it's something you have on your roadmap for sometime soon.
