Sounds like a perfect match for a traditional RDBMS (Relational Data Base Management System). There are quite a few very good open source alternatives to choose from, where PostgreSQL and MySQL probably are the most popular. You can also consider MariaDB, which is a non-Oracle fork of MySQL by the creator of MySQL.
PostgreSQL is perhaps the most traditional ...
A little late, but I will add my tip just for the record: https://www.schemacrawler.com/
It won't do the SQL generation, though, you'd have to do that yourself.
I've used it's output (as well as reflection info from JPA Entities) as input to JGraphT (create FK graph) to use topological sorting to find out where to start deleting rows without breaking FK ...
There is a tool called Domain Checker on RapidAPI platform.
You can use this to check the validity of a domain. The tool has a "Batch Request" feature that can validate a list of domain names. But you have to use the paid version to do that. This tool may be a good solution for your requirement
There the main open source tool designed to validation domain names (validation as correct DNS configuration) is Zonemaster (https://zonemaster.net).
The tool has a "batch mode" that can validate lists of domain names.
You can install it by following the installation instructions on Github: https://github.com/zonemaster/zonemaster