Node.js
You can find the bindings for node.js here. It's very easy to use and available from npm with:
npm install tulind
.NET (C#, Visual Basic, etc)
A .NET DLL is now available. It should work with .NET Framework and .NET Core, including 'Any-CPU' builds.
Python
Python bindings are available here.
Go
Go bindings by Daniel Murker are available here.
Ruby
Ruby bindings by Ezenwa Ogbonna are available here.
Excel VBA, Visual Basic
The Tulip Cell project provides bindings to Visual Basic for Applications, which is used in the Excel add-in. These bindings should also be easy to use for other windows programming languages that can call to a DLL.
C++
Tulip Indicators works well with C++. Just compile the C code; you shouldn't have any problems.
Swift
Swift bindings by Yannick Heinrich are available here.
Lua
Lua bindings are coming soon. They are already complete and used in Tulip Charts.