Langdi was a script commonly used by traders used to write Hindi, Punjabi, or Saraiki in the Indian subcontinent . Bookkeepers, known as munīm (Hindi: मुनीम, Urdu: مُنیم), would also keep records in this script.
Some scholars have claimed that Langdi is a form of Mahajani for writing in parts of Haryana. Its proper connection must be more thoroughly explored.
References
Langdi Wikipedia(Text) CC BY-SA