ContributionsMost RecentMost LikesSolutionsRe: Dictionaries mapping strings to Array? Thank you, ponelat, it totally solved my problem, it was exactly that. I thought that maybe an Array type would fit, but I had no idea how to specify the item's type. It seems very clear now. 😸 Dictionaries mapping strings to Array? Hello, you all. I aim to generate the spec through a NestJS project, and It's all working until now. The problem arises when I want to specify that return data is a Dict that maps a key to an array of custom objects. I read the documentation here https://swagger.io/docs/specification/data-models/dictionaries/ and some related content and got that I can create a map of strings to strings as: type: object additionalProperties: type: string but in, all examples I found I couldn't relate to an Array. This is an example of my data: { "1":[CustomObjectType, CustomObjectType, CustomObjectType], "5":[CustomObjectType, CustomObjectType, CustomObjectType] } So I think on Swagger it should be something like: components: schemas: CustomMap: type: object additionalProperties: $ref: '#/components/schemas/CustomObjectType' isArray: true CustomObjectType: type: object ... But I can't get it correctly. If I discover how I do it in Swagger, I can figure it out how to pass it to NestJS. Thank you to anyone who can help me. Solved