Large Language Model (LLM)
A neural network trained on large text corpora that generates human-like text.
Definition
A Large Language Model (LLM) is a deep learning model trained on massive text datasets that can understand and generate human language. Modern LLMs like GPT-4 and Claude can answer questions, write code, summarize documents, extract structured data, and perform complex reasoning tasks via a simple chat API.
Why it matters for AI APIs
LLMs are the core intelligence layer in modern AI products. Whether you're building a customer support bot, a document search tool, or a coding assistant, an LLM is what produces the intelligent output — but integrating one into a production system requires auth, rate limiting, streaming, token tracking, and billing infrastructure.
In FastAPI AI Kit
FastAPI AI Kit provides a unified LLM abstraction layer that wraps OpenAI, Anthropic, and any OpenAI-compatible model. Swap providers with a single env var change — your business logic never changes. Streaming SSE and token tracking are built in.