I found some accounts in DB but these accounts don't appear in SolarWinds, and I don't why they don't exist in SolarWinds? and Is it safe to remove them ?
Another aspect that influences the cost of custom software development is the type of software. For example, ecommerce websites need to be flexible enough to integrate with various external payment gateways. Booking apps and traffic analysis tools often require the integration of other external platforms. Custom software for an existing business may require data migration. Some developers will keep backups of your existing data in external databases https://mlsdev.com/services/mobile-app-development. These features, however, will increase the cost of custom software development.
In what database do you see these accounts? A db you are monitoring or the DPA repository database?