LLM inference, optimized for your Mac
Continuous batching and tiered KV caching, managed directly from your menu bar.
junkim.dot@gmail.com · https://omlx.ai/me
Install · Quickstart · Features · Models · CLI Configuration · Benchmarks · oMLX.ai
Every LLM server I tried made me choose between convenience and control. I wanted to pin everyday models in memory, auto-swap heavier ones on demand, set context limits - and manage it all from a menu bar.
oMLX persists KV cache across a hot in-memory tier and cold SSD tier - even when context changes mid-conversation, all past context stays cached and reusable across requests, making local LLMs practical for real coding work with tools like Claude Code. That's why I built it.
Download the .dmg from Releases, drag to Applications, done. The app includes in-app auto-update, so future upgrades are just one click. The macOS app also installs a lightweight ~/.omlx/bin/omlx CLI shim so terminal commands and Apple Shortcuts can control the app-managed server.
brew tap jundot/omlx https://github.com/jundot/omlx
brew install jundot/omlx/omlx --with-custom-kernel # With native custom kernels (needs full Xcode)
# No full Xcode? brew install jundot/omlx/omlx installs without the kernels
# Upgrade to the latest version
brew update && brew upgrade omlx
# Run as a background service (auto-restarts on crash)
omlx start
# Optional: MCP (Model Context Protocol) support, then restart to load it
/opt/homebrew/opt/omlx/libexec/bin/pip install mcp
omlx restartgit clone https://github.com/jundot/omlx.git
cd omlx
make install # Editable install with the web UI and native custom kernels
# No full Xcode? make install-no-kernels installs without the kernels
make mcp # Optional: MCP support, restart `omlx serve` to load itRequires macOS 15.0+ (Sequoia), Python 3.11–3.13, and Apple Silicon (M1/M2/M3/M4/M5).
Note on native custom kernels: GLM-5.2, MiniMax M3, and Qwen3.5 need them. Without them those families silently fall back to much slower generic paths -- for GLM-5.2 the fused DSA prefill is roughly 30x faster with the kernels (measured 845 vs ~29 tok/s on an M3 Ultra), and the fallback also uses more memory (#2137).
make installbuilds them and checks that each one loads. That needs full Xcode with the Metal toolchain (xcodebuild -downloadComponent MetalToolchain); Command Line Tools alone do not provide it (xcrun: error: unable to find utility "metal"). Without Xcode, use the official DMG, which ships the kernels precompiled, ormake install-no-kernels. A plainpip install -e .also skips them.make kernelsrebuilds only the kernels from scratch. Homebrew builds them with--with-custom-kernel, which also needs full Xcode. To verify any install:python -c "from omlx.custom_kernels import native_kernel_status; print(native_kernel_status())"
Launch oMLX from your Applications folder. The Welcome screen guides you through three steps - model directory, server start, and first model download. That's it. To connect OpenClaw, OpenCode, Codex, Hermes Agent, Copilot, or DeepSeek Harness, see Integrations.
# Managed background server (macOS app or Homebrew install)
omlx start
omlx stop
omlx restart
# Foreground server attached to this terminal
omlx serve --model-dir ~/modelsThe server discovers LLMs, VLMs, embedding models, and rerankers from subdirectories automatically. Any OpenAI-compatible client can connect to http://localhost:8000/v1. A built-in chat UI is also available at http://localhost:8000/admin/chat.
If you installed via Homebrew, you can run oMLX as a managed background service:
omlx start # Start via brew services
omlx stop # Stop
omlx restart # Restart
brew services start omlx # Start (auto-restarts on crash)
brew services stop omlx # Stop
brew services restart omlx # Restart
brew services info omlx # Check statusThe service runs omlx serve with zero-config defaults (~/.omlx/models, port 8000). omlx start, omlx stop, and omlx restart are the portable lifecycle commands; Homebrew installs delegate them to brew services. To customize, either set environment variables (OMLX_MODEL_DIR, OMLX_PORT, etc.) or run omlx serve --model-dir /your/path once to persist settings to ~/.omlx/settings.json.
Logs are written to two locations:
- Service log:
$(brew --prefix)/var/log/omlx.log(stdout/stderr) - Server log:
~/.omlx/logs/server.log(structured application log)
Supports text LLMs, vision-language models (VLM), OCR models, embeddings, and rerankers on Apple Silicon.
Web UI at /admin for real-time monitoring, model management, chat, benchmark, and per-model settings. Supports English, Korean, Japanese, Chinese, French, Russian, Spanish, and Brazilian Portuguese. All CDN dependencies are vendored for fully offline operation.
Source builds can split one downloaded language model across unequal-memory Macs using MLX pipeline ranks over Ring or Thunderbolt RDMA/JACCL. The Cluster dashboard handles read-only peer discovery, strict SSH/runtime verification, byte-aware unequal shard planning, measured compute/link rebalancing, headroom-aware execution tuning, activation, and a live shard/performance map on both Macs. Interactive, balanced, and throughput profiles expose coalesced batching, prompt-cache affinity, rotating-KV limits, Ring connection tuning, and a capability-gated experimental token-only output path. See Distributed inference across Macs for setup, security boundaries, current limitations, and the physical-hardware validation checklist.
A paired Mac can also speed up prefill without splitting the model: the Prefill Accelerator runs the first layers of long prompts on the other Mac while the model, its cache and decoding stay on this one (DeepSeek V4.1, GLM-5.3, Qwen3.8 Flash-Next, Qwen3.8 27B and MiniMax M3). The helper can also be a Linux machine with NVIDIA GPUs running omlx-cuda-helper.
Run VLMs with the same continuous batching and tiered KV cache stack as text LLMs. Supports multi-image chat, base64/URL/file image inputs, and tool calling with vision context. MiMo V2.6 checkpoints with bundled sidecars also accept sampled-frame video and 24 kHz audio. Qwen3.5, Qwen3.6 and Qwen3.8 checkpoints (dense and MoE) accept native video input as base64 video_url / input_video data URIs; video needs OpenCV (opencv-python-headless). oQ conversion of official MiMo V2.6 checkpoints preserves image and audio support. OCR models (DeepSeek-OCR, DOTS-OCR, GLM-OCR) are auto-detected with optimized prompts.
Block-based KV cache management inspired by vLLM, with prefix sharing and Copy-on-Write. The cache operates across two tiers:
- Hot tier (RAM): Frequently accessed blocks stay in memory for fast access.
- Cold tier (SSD): When the hot cache fills up, blocks are offloaded to SSD in safetensors format. On the next request with a matching prefix, they're restored from disk instead of recomputed from scratch - even after a server restart.
Optional Affine4 and Affine8 KV compression add signed 4-bit and 8-bit cache formats with Metal TensorOps decode attention and a portable fallback. Select either under Model settings → Memory Saving → KV cache compression.
Handles concurrent requests through mlx-lm's BatchGenerator. Max concurrent requests is configurable via CLI or admin panel.
Runs smaller context models with Claude Code by reporting the model's real context window to auto-compact instead of scaling token counts, and SSE keep-alive prevents read timeouts during long prefill.
Load LLMs, VLMs, embedding models, and rerankers within the same server. Models are managed through a combination of automatic and manual controls:
- LRU eviction: Least-recently-used models are evicted automatically when memory runs low.
- Manual load/unload: Interactive status badges in the admin panel let you load or unload models on demand.
- Model pinning: Pin frequently used models to keep them always loaded.
- Per-model TTL: Set an idle timeout per model to auto-unload after a period of inactivity.
- Process memory enforcement: Total memory limit (default: system RAM - 8GB) prevents system-wide OOM.
Configure sampling parameters, chat template kwargs, TTL, model alias, model type override, and more per model directly from the admin panel. Changes apply immediately without server restart.
- Model alias: set a custom API-visible name.
/v1/modelsreturns the alias, and requests accept both the alias and directory name. - Model type override: manually set a model as LLM or VLM regardless of auto-detection.
- External engine: serve the models Splash supports, including GGUF files, from your model directories on Splash's Metal engine in its own process. See docs/Splash.md for the supported models and Splash versions.
- Profiles: save named bundles of per-model settings and switch between them from the admin panel. A profile can optionally be exposed as its own model:
/v1/modelsthen also lists<model>:<profile>(e.g.qwen3-8b:thinking), which serves on the same engine as the base model with the profile's settings overlaid per request — no extra memory, no reload. When the base model has an alias, the exposed ID is advertised as<alias>:<profile>; the directory-name form keeps working, just like for the base model.
Chat directly with any loaded model from the admin panel. Supports conversation history, model switching, dark mode, reasoning model output, and image upload for VLM/OCR models.
Document attachments support PDF, DOCX, PPTX, TXT, and MD. Attachments are accepted by filename extension. If the client reports a MIME type oMLX does not recognize, such as application/octet-stream, the converter MIME type is inferred from the extension.
Search and download models from HuggingFace directly in the admin dashboard, in MLX, GGUF or all formats. Browse model cards, then pick the files to download: an MLX checkpoint keeps the files it needs, and a GGUF brings its vision projector.
Set up OpenClaw, OpenCode, Codex, Hermes Agent, Copilot, Pi, Mistral Vibe, and DeepSeek Harness directly from the admin dashboard with a single click. No manual config editing required.
omlx launch codex and omlx launch codex_app give Codex a catalog of every chat model on the server, so you switch models with /model or the app's model picker. --model, the saved Codex model, or the server default picks the starting model. This needs Codex 0.148 or newer; relaunch after you add or remove models.
omlx launch copilot gives Copilot CLI a catalog of every chat model on the server, so you switch models with /model. --model, the saved Copilot model, or the server default picks the starting model. The catalog goes into Copilot's providers.json next to your other providers, and the file is kept at 0600 because it holds the server's API key. This needs Copilot CLI 1.0.83 or newer; relaunch after you add or remove models.
Install Mistral Vibe 2.26.0 or newer with uv tool install mistral-vibe, then run omlx launch vibe to select a local model, or omlx launch vibe --model <model-id>. Vibe's provider, model, API-key reference and context window are configured for that process through its VIBE_* environment overrides. Existing config.toml, VIBE_HOME, tool permissions and cloud configuration are preserved. Pass Vibe arguments after --, for example omlx launch vibe --model <model-id> -- --resume.
One-click benchmarking from the admin panel. Measures prefill (PP) and text generation (TG) tokens per second, with partial prefix cache hit testing for realistic performance numbers.
Native Swift / SwiftUI menubar app (not Electron). Start, stop, and monitor the server without opening a terminal. Includes local usage history with per-model totals and an hourly heatmap, persistent serving stats (survives restarts), auto-restart on crash, and built-in auto-update.
Drop-in replacement for OpenAI and Anthropic APIs. Supports streaming usage stats (stream_options.include_usage), llama.cpp-style prefill progress (return_progress), Anthropic adaptive thinking, and vision inputs (images as base64 or URL, video as base64).
| Endpoint | Description |
|---|---|
POST /v1/chat/completions |
Chat completions (streaming) |
POST /v1/completions |
Text completions (streaming) |
POST /v1/messages |
Anthropic Messages API |
POST /v1/embeddings |
Text embeddings |
POST /v1/rerank |
Document reranking |
POST /v1/systemone |
Typed decisions with decision models or chat models (TypeSafe System One) |
GET /v1/models |
List available models |
POST /tokenize, POST /detokenize |
vLLM-compatible tokenizer API (also under /v1) |
The admin API for settings, models, downloads, quantization, and benchmarks takes the main API key as a Bearer token and also works in headless mode. See Admin API.
Supports all function calling formats available in mlx-lm, JSON schema validation, and MCP tool integration. Tool calling requires the model's chat template to support the tools parameter. The following model families are auto-detected:
| Model Family | Format |
|---|---|
| Llama, Qwen, DeepSeek, etc. | JSON <tool_call> |
| Qwen3.5 Series, Raon-1 mini | XML <function=...> |
| Gemma | <start_function_call> |
| GLM (4.7, 5) | <arg_key>/<arg_value> XML |
| MiniMax | Namespaced <minimax:tool_call> |
| Mistral | [TOOL_CALLS] |
| IFM K2 Horizon | XML or JSON inside <ifm|tool_calls>. Requires omlx[grammar] |
| Kimi K2 | <|tool_calls_section_begin|> |
| Longcat | <longcat_tool_call> |
Models not listed above may still work if their chat template accepts tools and their output uses a recognized <tool_call> XML format. For tool-enabled streaming, assistant text is emitted incrementally while known tool-call control markup is suppressed from visible content; structured tool calls are emitted after parsing the completed turn.
A bare JSON, EBNF, or regex grammar constrains the answer from the first generated token, so thinking_budget is ignored. Configure a compatible reasoning_parser to combine constrained output with a separate, budgeted reasoning phase.
Point --model-dir at a directory containing MLX-format model subdirectories. Two-level organization folders (e.g., mlx-community/model-name/) are also supported. GGUF files in these folders are listed one model per file and run on an external engine.
~/models/
├── Step-3.5-Flash-8bit/
├── Qwen3-Coder-Next-8bit/
├── gpt-oss-120b-MXFP4-Q8/
├── Qwen3.5-122B-A10B-4bit/
└── bge-m3/
Models are auto-detected by type. You can also download models directly from the admin dashboard.
| Type | Models |
|---|---|
| LLM | Any model supported by mlx-lm |
| VLM | Qwen3.5 Series, GLM-4V, Pixtral, and other mlx-vlm models |
| OCR | DeepSeek-OCR, DOTS-OCR, GLM-OCR |
| Embedding | BERT, BGE-M3, ModernBERT, EmbeddingGemma 2 |
| Reranker | ModernBERT, XLM-RoBERTa |
| Decision | Clef, Clef-Flash, OpenJev, Decision 3.0 (d3, d3-flash, d3-mini, d3-nano, d3-lite, d3-edge) |
# Managed background server (macOS app or Homebrew install)
omlx start
omlx stop
omlx restart
# Start with default settings (memory guard tier = balanced, manage via admin UI)
omlx serve --model-dir ~/models
# Choose a memory guard tier at startup
omlx serve --model-dir ~/models --memory-guard safe
# Set a custom memory guard ceiling in GB
omlx serve --model-dir ~/models --memory-guard-gb 48
# Enable SSD cache for KV blocks
omlx serve --model-dir ~/models --paged-ssd-cache-dir ~/.omlx/cache
# Set in-memory hot cache size
omlx serve --model-dir ~/models --hot-cache-max-size 20%
# Adjust max concurrent requests (default: 8)
omlx serve --model-dir ~/models --max-concurrent-requests 16
# With MCP tools
omlx serve --model-dir ~/models --mcp-config mcp.json
# HuggingFace mirror endpoint (for restricted regions)
omlx serve --model-dir ~/models --hf-endpoint https://hf-mirror.com
# API key authentication
omlx serve --model-dir ~/models --api-key your-secret-key
# Localhost-only: skip verification via admin panel global settings
# Network access requires authentication
OMLX_API_KEY=your-secret-key omlx serve --model-dir ~/models --host 0.0.0.0
# Inference and admin APIs only, without the web UI (not saved to settings)
omlx serve --model-dir ~/models --headlessThe default SSD cache limit, auto, uses 50% of the sum of free disk space and existing SSD cache files, including GDN sidecars. The budget is refreshed during use and does not shrink simply because the cache grows or the server restarts. Other disk usage can change the budget. Set --paged-ssd-cache-max-size 20GB for a fixed limit.
Most settings can also be configured from the web admin panel at /admin. Settings are persisted to ~/.omlx/settings.json, and CLI flags take precedence.
Set the main API key before changing the server host to a LAN address or 0.0.0.0, or save both settings together. oMLX refuses to start on any non-loopback address without a main API key. "Disable all authentication" (skip_api_key_verification) turns off both inference and admin authentication, so it stays restricted to loopback-only binds.
For keyless inference on a network bind, turn on "Allow inference without API key" in the web admin settings or the Security screen of the macOS app. It sets auth.allow_unauthenticated_inference, defaults to false, and applies without a restart. This allows anyone who can reach the server to use inference (including stored Responses and audio), MCP tools, and web search. Management endpoints still require the main API key or an admin login.
Architecture
FastAPI Server (OpenAI / Anthropic API)
│
├── EnginePool (multi-model, LRU eviction, TTL, manual load/unload)
│ ├── BatchedEngine (LLMs, continuous batching)
│ ├── VLMEngine (vision-language models)
│ ├── EmbeddingEngine
│ ├── RerankerEngine
│ └── DecisionEngine
│
├── ProcessMemoryEnforcer (total memory limit, TTL checks)
│
├── Scheduler (FCFS, configurable concurrency)
│ └── mlx-lm BatchGenerator
│
└── Cache Stack
├── PagedCacheManager (GPU, block-based, CoW, prefix sharing)
├── Hot Cache (in-memory tier, write-back)
└── PagedSSDCacheManager (SSD cold tier, safetensors format)