Jinja.cpp: A single-header C++11 Jinja2 template engine for LLM chat templates (github.com)

Jinja.cpp is a newly introduced lightweight, single-header C++11 template engine tailored specifically for integrating Jinja2 templates with Large Language Models (LLMs) like Llama 3 and Qwen 2.5/3. This library facilitates seamless inference in C++ environments by supporting native message structures, tools, and special tokens essential for LLMs, offering a significant advancement for developers in the AI/ML community looking to leverage C++ for machine learning applications. The engine is designed for compatibility with older C++ compilers and embedded systems, minimizing dependencies to just the nlohmann/json library. Its strict typing and the ability to inject custom C++ functions into templates enhance functionality and control. The library has been rigorously tested against official outputs from various models using fuzzy matching, ensuring robustness. By simplifying the process of creating chat templates and managing contextual data, Jinja.cpp empowers developers to build more efficient and integrated AI solutions, particularly in scenarios where performance and compatibility are critical.