AIKit is an open-source tool designed to simplify the process of hosting, deploying, building, and fine-tuning large language models (LLMs). It offers a REST API compatible with the OpenAI API, supporting various inference capabilities and formats, allowing users to send requests using any compatible client. Furthermore, AIKit provides an extensible fine-tuning interface with Unsloth support, offering users a fast, memory-efficient, and user-friendly fine-tuning experience.