[bsmth]

You might be interested in data attributes for this use case https://developer.mozilla.org/en-US/docs/Web/HTML/How_to/Use... although it depends on the shape of the JSON data you had in mind.

[alserio]

What do you mean with shape? Are you concerned about escaping and such?

[bsmth]

I can imagine if it's deeply nested data, your markup might get complex, but the structure of the HTML doesn't have to mirror the JSON. There's other examples here which might illustrate more how this can look: https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/...