I don't think the latency issues are necessarily related to the poor schema. I'd say to dig into the query planning for your current queries and figure out what

I don't think the latency issues are necessarily related to the poor schema. I'd say to dig into the query planning for your current queries and figure out what's actually slow, since it may not be what you expect. Rearchitecting the schema might be worth doing. From the technical side, PG is pretty nice about doing transactional schema changes. I'd be more worried about the data though. Are you sure that every single row's Json columns have the keys and value types that you expect? Usually in this type of database, some records will be weird in unexpected ways. You'll need to find and account for them all before you can migrate over to a stricter schema. And do any of them have extra unexpected data?