WSDL - at what stage of the project would you expect delivery?

I'm working on my first project using an external supplier, who will develop some web services for the company I work for.

My question is - at what stage of the project lifecycle would you expect the WDSL (and any associated Schemas) to be delivered?

Personally, I think it's a service contract, so I wouldn't expect it to be unreasonable to be delivered at functional design stage; although I gue开发者_开发知识库ss you could argue so long as it's all documented (names, lengths, formats, etc.) in a functional spec document that's ok. And the WDSL itself would be delivered at component design / development stage?

I would expect the WSDL to be available early on the development process. The implementation of the web service can happen in parallel. It will help both you and the vendor to get the WSDL up and running as soon as possible after design has been finalized.