tDev what? tDev is a tool for mod makers. It's basically an addition to tAPI (tested with 14.a) with a few little tweaks geared towards developing and debugging your mod: Uses a completely separate game folder. Where tAPI uses "My Games\Terraria\tAPI", tDev uses "My Games\Terraria\tDev". Never break your main game again when you accidentally use an unstable mod on your favourite world! Lets you start the game with a debugger attached. It seems that tAPI has a bug where you can attach after the game is started, but only then. That's fixed now. Lets you "Edit and Continue". That's right, grab an edition of Visual Studio, and off you go. Break, fix, run again - with no restarts required. Lets you build your mod from the command line. Finally, developing a mod gets to be really seamless - just set up a post-build task, and you're done. tDev how? How do I use it, you mean? If you're asking how it works, well, use the source, Luke. (tl;dr - patches tAPI with Mono.Cecil) Download tDev and put it in your Terraria game folder. Same folder where tAPI.exe is. You have two files - tDev.exe is the game, and tDev.Build.exe is a command-line mod builder. Run tDev now. It will create its own config folder. Set up your Visual Studio project as follows: Assumptions: Your username is "Mark IV McAwesome" Your mod is called Mark.SuchAwesomeMod (internal name) Your mod's source is in "C:\Code\Mark's Mod" You installed the game in "C:\Games\Terraria" Setup: Add references to tAPI.exe and all Microsoft.Xna.*.dll files Use [ "C:\Games\Terraria\tDev.exe" ] as your startup executable. Use [ "C:\Games\Terraria\tDev.Build.exe" Mark.SuchAwesomeMod "C:\Code\Mark's Mod" ] as a post-build task. Use [ "C:\Users\Mark IV McAwesome\Documents\My Games\Terraria\tDev\Mods\PDB" ] as your output path. Yeah, we're using the PDB folder for our assembly, due to the way I hacked around the mod loader. Don't ask, don't tell. (This last step is only needed if you intend to use "Edit and Continue", without it the mod will still load.) When you're done with development, you can copy your mod package from "C:\Users\John\Documents\My Games\Terraria\tDev\Mods\Local", and put it in your main tAPI folder. Or just double-click it and let tAPI do that. tDev where? tDev on Dropbox. Download here (v1.0). Or you can get the sources. Don't expect much, the builder for the tDev binary is just an elaborate patcher of tAPI. tDev I have other questions! Ask away, I'll do my best to respond. I wrote this for myself, but maybe someone else could use it.