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llmmllab-api: An OpenAI/Anthropic Compatible Inference Service Based on llama.cpp

A Python FastAPI-based inference service that provides OpenAI and Anthropic compatible API endpoints, supports llama.cpp backend and LangGraph agent orchestration, and is suitable for private LLM deployment.

LLM 推理FastAPIllama.cppOpenAI 兼容私有化部署LangGraphKubernetesAPI 服务
Published 2026-05-01 00:45Recent activity 2026-05-01 00:54Estimated read 5 min
llmmllab-api: An OpenAI/Anthropic Compatible Inference Service Based on llama.cpp
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Section 01

Introduction / Main Floor: llmmllab-api: An OpenAI/Anthropic Compatible Inference Service Based on llama.cpp

A Python FastAPI-based inference service that provides OpenAI and Anthropic compatible API endpoints, supports llama.cpp backend and LangGraph agent orchestration, and is suitable for private LLM deployment.

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Section 02

Project Overview and Positioning

llmmllab-api is an LLM inference service built on Python FastAPI, aiming to provide endpoints compatible with OpenAI and Anthropic API formats. The project combines the high-performance inference capabilities of llama.cpp and the agent orchestration features of LangGraph, offering a complete solution for teams needing private deployment of large language models.

The core positioning of the project is "compatibility first"—by simulating the API formats of mainstream cloud service providers, existing client code can switch to privately deployed model services without modification. This design greatly reduces the threshold for migrating from cloud APIs to local deployment.

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Section 03

FastAPI Service Layer

The project uses FastAPI as the web framework, leveraging its native asynchronous support and automatic API documentation generation features. After the service starts, developers can directly access the /docs path to view the interactive API documentation, which facilitates testing and integration.

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Section 04

Multi-Provider Compatible Endpoints

The system implements two main routing systems:

  • OpenAI-compatible routes (/openai/): Supports standard endpoints such as chat.completions and embeddings
  • Anthropic-compatible routes (/anthropic/): Supports Claude series APIs like messages

This dual-compatibility strategy ensures that existing clients using any cloud service provider's SDK can seamlessly switch to llmmllab-api.

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Section 05

llama.cpp Inference Backend

The project uses llama.cpp as the underlying inference engine, which is a high-performance LLM inference library written in C/C++. It supports multiple quantization formats (GGUF) and can run large models on consumer-grade hardware. The Docker image compiles llama.cpp from source and enables CUDA support to fully utilize GPU acceleration.

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Section 06

LangGraph Agent Orchestration

The project integrates the LangGraph framework, providing:

  • Workflow Orchestration API (composer_init.py): Defines and manages complex multi-step AI workflows
  • Graph Structure Builder (graph/): Visualizes workflow nodes and state management
  • Tool Registry (tools/): Unified management of static and dynamic tools

This makes llmmllab-api not just a simple inference service, but also an orchestration platform that supports agent collaboration.

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Section 07

Project Structure and Code Organization

The project adopts a clear layered architecture with well-defined responsibilities for each module:

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Section 08

Core Entry and Routes

  • app.py: FastAPI application entry point, responsible for application initialization and middleware mounting
  • routers/: API route definitions, organized by provider (openai/, anthropic/) and common functions (common/)