While looking through the code in the mocks package I noticed this TODO comment about allowing passing a seed so that results could be more deterministic (https://github.com/ardatan/graphql-tools/blob/master/packages/mock/src/mocking.ts#L73-L75) . I would find this feature very useful for testing as well as other use cases. If you would like I would be willing to open a PR if you think it would be useful for other people as well.