# Technology Stack

**Analysis Date:** 2026-03-28

## Languages

**Primary:**
- Rust 2021 - core backend, inference runtime, CLI, shared contracts, metrics, and Tauri desktop backend in `Cargo.toml`, `crates/inference-server/src/main.rs`, `crates/inference-core/src/engine.rs`, `crates/localllm-cli/src/main.rs`, and `tauri-app/src-tauri/src/lib.rs`
- TypeScript 5.5 - desktop frontend, runtime manager UI, chat UI, and tests in `tauri-app/package.json`, `tauri-app/src/App.tsx`, and `tauri-app/src/features/runtime/components/RuntimeSettingsDrawer.tsx`

**Secondary:**
- CSS - hand-authored styling with app-wide tokens and feature CSS modules in `tauri-app/src/index.css`, `tauri-app/src/components/Sidebar.css`, and `tauri-app/src/components/ChatView.css`
- Markdown - product and architecture docs in `README.MD`, `docs/api/overview.md`, and `docs/app/overview.md`
- Python - benchmark and experiment scripts in `experiments/bench_chat_latency.py`, `experiments/bench_cli_surface.py`, and related files under `experiments/`

## Runtime

**Environment:**
- Rust toolchain targeting native desktop/server binaries; no workspace-level rust-toolchain file detected
- Node.js runtime for Vite/Tauri frontend workflows in `tauri-app/package.json`

**Package Manager:**
- Cargo for Rust workspace dependencies and binaries in `Cargo.toml`
- npm is the documented frontend package manager via `README.MD:47`; lockfiles for npm and pnpm are both present in `tauri-app/package-lock.json` and `tauri-app/pnpm-lock.yaml`
- Lockfile: present for Rust and frontend in `Cargo.lock` and `tauri-app/package-lock.json`

## Frameworks

**Core:**
- Axum 0.8 - local HTTP API in `Cargo.toml` and `crates/inference-server/src/routes.rs`
- React 18 - desktop UI shell and chat surface in `tauri-app/package.json` and `tauri-app/src/App.tsx`
- Tauri 2 - desktop shell, local process control, file dialogs, and frontend-to-Rust command bridge in `tauri-app/src-tauri/Cargo.toml` and `tauri-app/src-tauri/src/lib.rs`
- llama.cpp FFI via custom `llama-sys` - model loading and token generation in `crates/inference-core/src/engine.rs` and `crates/inference-core/src/session.rs`

**Testing:**
- Vitest 4 - frontend/unit/component tests in `tauri-app/package.json` and `tauri-app/src/features/runtime/components/RuntimeSurface.test.tsx`
- Rust built-in test harness - backend/unit tests co-located in files such as `crates/api-contracts/src/chat.rs` and `tauri-app/src-tauri/src/runtime/state.rs`

**Build/Dev:**
- Vite 5 - frontend dev/build tool in `tauri-app/vite.config.ts`
- TypeScript compiler - typecheck step in `tauri-app/package.json:9`
- Tauri CLI 2 - desktop dev/build entry in `tauri-app/package.json:11`

## Key Dependencies

**Critical:**
- `tokio` - async runtime for API server in `Cargo.toml` and `crates/inference-server/src/main.rs`
- `tower-http` - CORS and trace middleware in `Cargo.toml` and `crates/inference-server/src/compat.rs`
- `serde` / `serde_json` - shared request/response contracts across API, CLI, and Tauri in `crates/api-contracts/src/chat.rs` and `tauri-app/src-tauri/src/runtime/config.rs`
- `clap` - CLI command surface in `crates/localllm-cli/src/main.rs`
- `ureq` - synchronous HTTP transport for CLI live execution in `crates/localllm-cli/src/main.rs:404`
- `marked`, `dompurify`, `highlight.js` - markdown rendering/sanitization/code highlighting in `tauri-app/src/lib/markdown.ts`
- `@tauri-apps/api` and `@tauri-apps/plugin-shell` - frontend/Tauri bridge in `tauri-app/package.json` and `tauri-app/src/features/runtime/api.ts`

**Infrastructure:**
- `uuid` - response IDs for chat completions in `crates/inference-server/src/routes.rs:126`
- `tracing` and `tracing-subscriber` - backend logging and startup diagnostics in `crates/inference-server/src/main.rs`
- `async-stream` - SSE streaming implementation in `crates/inference-server/Cargo.toml` and `crates/inference-server/src/routes.rs:137`

## Configuration

**Environment:**
- Backend runtime is environment-driven via `LOCALLLM_MODEL`, `LOCALLLM_PROFILE`, `LOCALLLM_ADDR`, `LOCALLLM_GPU_LAYERS`, `LOCALLLM_CTX`, `LOCALLLM_API_KEY`, `LOCALLLM_CORS_ORIGINS`, `LOCALLLM_AUTH_HEADER`, `LOCALLLM_AUTH_SCHEME`, `LOCALLLM_SYSTEM_PROMPT`, and `LOCALLLM_MODEL_ALIASES` in `crates/inference-server/src/main.rs` and `crates/inference-server/src/compat.rs`
- Desktop runtime config is persisted as JSON in the app data directory through `tauri-app/src-tauri/src/runtime/config.rs`
- Frontend fallback runtime snapshot is persisted in `localStorage` through `tauri-app/src/features/runtime/api.ts`

**Build:**
- Rust workspace build in `Cargo.toml`
- Tauri desktop build in `tauri-app/src-tauri/Cargo.toml` and `tauri-app/src-tauri/tauri.conf.json`
- Frontend dev server/build in `tauri-app/vite.config.ts` and `tauri-app/package.json`

## Platform Requirements

**Development:**
- Rust + Cargo for backend and desktop backend in `README.MD:56`
- Node.js/npm for the Tauri frontend in `README.MD:57`
- Local `.gguf` model for real inference in `README.MD:58`
- Optional NVIDIA GPU for accelerated local runtime; CPU fallback profile exists in `README.MD:59` and `crates/inference-core/src/profile.rs`

**Production:**
- Local-first desktop deployment via Tauri app in `tauri-app/`
- Local HTTP API deployment as standalone binary `localllm` in `crates/inference-server/Cargo.toml:8`

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*Stack analysis: 2026-03-28*