This actually seems really hard to do better than what openrouter already has

• service needs to be able to bill the user, or they have to preload money into it (openrouter preloads money)
• user needs to be able to quickly approve the key and probably set a limit to prevent error or abuse (openrouter does this)
• whole thing should be like 1-2 clicks (openrouter)
• should be a shelling point service where support and users are clustered (arguably openrouter is best positioned)
• should hopefully be able to serve pretty much any llm, not be vender locked (openrouter)