Dataherald is an open-source, NL-to-SQL engine designed to enhance the accuracy and efficiency of translating natural language queries into SQL. Built on LangChain and using LangSmith for observability, Dataherald allows users to add business context, create training data, and fine-tune language models to their database schemas. It features two LangChain agents: a RAG-only agent for scenarios lacking extensive training data, and a more advanced agent utilizing a fine-tuned LLM-as-a-tool once sufficient golden SQL samples are available. These agents access databases to ensure syntactic and semantic accuracy in SQL generation, allowing developers to improve performance through a user-friendly interface. By enabling companies from startups to Fortune 500s to develop conversational interfaces and self-service data solutions, Dataherald aims to simplify the complex process of NL-to-SQL conversion, with future plans to enhance its integration with LangChain and expand support for open-source LLMs.