If you're looking for a platform with prebuilt formats to generate JSON data, JSON Data AI is a great option. The tool lets you generate custom JSON data based on prompts and convert it into live API endpoints. There are prebuilt formats for a variety of subjects, and you can customize it by defining object fields. The Pro version offers more features like improved accuracy and the ability to save and edit responses, so it's a good option for quick data generation.
Another option is SpeakStruct, which converts voice input into structured data formats using customizable templates. Although its primary purpose is converting voice to structured data, you can also use it to generate JSON data. The platform is geared for professionals and businesses that need to capture voice input and convert it into consistent, structured formats, so it's good for a variety of use cases like sales and customer support.