Initial MVP: multiplexer + chat DB

README.md

@@ -0,0 +1,65 @@
+# llm-backend
+
+Backend API for:
+- LLM multiplexer (OpenAI / Anthropic / xAI (Grok))
+- Personal chat database (chats/messages + LLM call log)
+
+## Stack
+- Node.js + TypeScript
+- Fastify (HTTP)
+- Prisma + SQLite (dev)
+
+## Quick start
+
+```bash
+cd llm-backend
+cp .env.example .env
+npm run db:migrate
+npm run dev
+```
+
+Open docs: `http://localhost:8787/docs`
+
+## Auth
+
+Set `ADMIN_TOKEN` and send:
+
+`Authorization: Bearer <ADMIN_TOKEN>`
+
+If `ADMIN_TOKEN` is not set, the server runs in open mode (dev).
+
+## Env
+- `OPENAI_API_KEY`
+- `ANTHROPIC_API_KEY`
+- `XAI_API_KEY`
+
+## API
+- `GET /health`
+- `GET /v1/chats`
+- `POST /v1/chats`
+- `GET /v1/chats/:chatId`
+- `POST /v1/chats/:chatId/messages`
+- `POST /v1/chat-completions`
+
+`POST /v1/chat-completions` body example:
+
+```json
+{
+  "chatId": "<optional chat id>",
+  "provider": "openai",
+  "model": "gpt-4.1-mini",
+  "messages": [
+    {"role":"system","content":"You are helpful."},
+    {"role":"user","content":"Say hi"}
+  ],
+  "temperature": 0.2,
+  "maxTokens": 256
+}
+```
+
+## Next steps (planned)
+- SSE streaming (`/v1/chat-completions:stream`)
+- Tool/function calling normalization
+- User accounts + per-device API keys
+- Postgres support + migrations for prod
+- Attachments + embeddings + semantic search