Vita's technology has developed largely on par with Earth technology in the mid-to-late Victorian era (roughly speaking, the 19th century). There are, however, minor exceptions; some technology (e.g. the gun and locomotive engine) has developed more slowly, while other technology (e.g. the aeroship) has developed at an advanced rate. Other technology, such as the seer stone and the phosphor lantern, is entirely different from Earth technology.
If you're not sure about something that isn't mentioned on this page, check to see if it was invented on Earth pre-1890, or ask a moderator.
You might ask, "Can my character invent new technology that doesn't seem to exist in Vita?"
The answer: talk to a moderator. If the technology is not listed on this page, but was invented before 1890, it may already exist in the Thorniverse. If it does not exist, it's probably for a good reason. Some aspects of Vitan technology are lagging behind, typically due to political or social dynamics that didn't exist in our world in the Victorian era.
If the technology you want to invent is something that was invented post-1890 (or if you want to create something that would become a de facto replacement for that thing, through magic or some other means), the answer will probably be no. We want to keep our timeline secure against radical developments that would alter society in a huge way. You, as the player, obviously have access to technological or scientific knowledge that Vitans would not have. The trick is to play the game as though you were not privy to this information. It would be unfair if players could use their modern knowledge, which was hard-won by generations of very intelligent people, to invent things that shouldn't exist yet.
Advancements and improvements upon current Vitan technology may be acceptable, but only if there is a good reason for it; talk to a moderator before pursuing a plotline in which your character significantly advances technology, especially if would essentially change the world.