Postgraphile comes immediately to my mind. https://www.graphile.org/postgraphile/smart-tags-file/ https://www.graphile.org/postgraphile/smart-tags-file/ JSON5

Postgraphile comes immediately to my mind. https://www.graphile.org/postgraphile/smart-tags-file/ https://www.graphile.org/postgraphile/smart-tags-file/ JSON5 parsing is unfortunately slower than JSON. Not intrinsically, but JSON.parse/stringify are both natively implemented and highly optimized. If browsers started supporting it, it would take off overnight. I can't tell you how often I've wanted to put comments or not worry about removing the last trailing comma from a list. It would win for some of the same reasons HTML5 beat XHTML. Ease of use and implicit rules beat pedantic strictness any day of the week. "Programmers are lazy."