LLM Viewer

LLM Viewer is a local proxy and request inspector for Anthropic-compatible APIs. It forwards streaming and non-streaming requests and records their responses for inspection in a web UI.

OpenAI-compatible endpoints are not supported yet.

Install

Node.js 20 or later is required.

Run with npm:

npx llm-viewer

Or install globally:

npm install --global llm-viewer
llm-viewer

To run from source:

git clone [email protected]:tyler66737/llm-viewer.git
cd llm-viewer
npm install
npm run build
npm start

Open http://127.0.0.1:8787 after startup.

Configure

Open Settings in the web UI to configure:

• Anthropic-compatible base URL
• Optional full Messages URL
• Optional server-side API key
• Local record directory

The default upstream is:

https://api.anthropic.com/v1/messages

For DeepSeek, set the base URL to:

https://api.deepseek.com/anthropic

If no server-side API key is configured, the proxy forwards the client's x-api-key header.

Use

Point the client's Anthropic base URL to:

http://127.0.0.1:8787/anthropic

Example request:

curl http://127.0.0.1:8787/anthropic/v1/messages \
  -H 'content-type: application/json' \
  -H 'anthropic-version: 2023-06-01' \
  -H 'x-api-key: YOUR_API_KEY' \
  -d '{
    "model": "claude-sonnet-4-5",
    "max_tokens": 256,
    "stream": true,
    "messages": [{"role": "user", "content": "Hello"}]
  }'

CLI Options

llm-viewer --host 127.0.0.1 --port 8787
llm-viewer --help

The server listens on 127.0.0.1:8787 by default. Binding to 0.0.0.0 exposes the UI and APIs to the local network.

Local Data

~/.llm-viewer/
├── settings.json
└── data/
    ├── index.json
    └── records/

License

MIT