We recently checked in a new feature which we call offline validation or validate by direct input. You can now see a new tab at
http://validator.odata.org which says "By Direct Input".
This provides the ability to directly validate a payload. We added a tab on the UI called "By Direct Input" where you can paste the text of the payload to be validated. Optionally you can also paste the $metadata payload corresponding to the service
which will help the validation engine to execute more rules that apply to the given payload. Rest of the validation works just like validation from a given endpoint URI.
One difference between validating By Uri and By Direct Input though is the number of rules that were executed. There are some rules that validate Http headers which cannot be executed in the By Direct Input case. We thought about ability to paste the headers
payload as well (e.g. pasting a whole trace from a tool like Fiddler) but it'd make the payload parsing more complicated without a huge value.
We thought in its current form the validate by direct input is simple enough and provides quick value. We think this is going to be useful for users whose service is behind a firewall or authenticated not allowing the OData Service Validation tool to
access and fetch the payload to validate. In these cases, you can always download the source and run the system locally, but the offline validation feature is handy if you would like to quickly try and validate your payload.
Please try it out and let us know if you have any feedback.