Core ML
by Apple Inc. · Framework · also known as CoreML, coremltools
Apple's on-device machine-learning runtime for iOS and macOS apps, with the open-source coremltools package for converting PyTorch and other models to its format
Overview
Core ML is Apple's framework for running machine-learning models inside apps on iPhone, iPad, Mac, Apple Watch, Apple TV and Vision Pro. A model is packaged in the Core ML format (.mlmodel or .mlpackage), bundled with the app and executed on the device, where the framework schedules work across CPU, GPU and the Neural Engine. It underlies Apple's higher-level Vision, Natural Language, Speech and Sound Analysis frameworks and supports on-device fine-tuning of updatable models.
Models reach Core ML in two ways: Create ML trains common model types directly, and the open-source Python package coremltools (BSD-3-Clause, maintained by Apple on GitHub) converts models from PyTorch, TensorFlow and other libraries, applying quantization, palettization and pruning to reduce size. Xcode shows a model's inputs, outputs and performance report and generates a typed Swift interface.
Core ML is the deployment route for shipping a model in an Apple app; it is not a training framework and is not available outside Apple platforms. Conversion can fail for operators coremltools does not support, and very large language models are constrained by device memory and conversion effort, which is why MLX is often used for research and Core ML for shipping.
Capabilities
- On-device inference across CPU, GPU and Neural Engine
- Model conversion from PyTorch and TensorFlow with coremltools
- Quantization, palettization and pruning for compact models
- Typed Swift interfaces generated by Xcode
- On-device updates of updatable models
- Foundation for Vision, Natural Language and Speech frameworks
Typical workflows
- Convert a PyTorch classifier and ship it in an iOS app
- Profile a model's latency per compute unit in Xcode
- Run image analysis offline with Vision on top of Core ML
Strengths
- Inference stays on the device; no network or server cost
- Hardware scheduling handled by the system
- Open-source conversion tooling
Limitations
- Apple platforms only
- Not a training framework
- Unsupported operators block conversion
- Large models constrained by device memory
Prerequisites
- Xcode and an Apple platform target
- Python with coremltools for conversion
Who it is for
- iOS and macOS developers embedding ML
- ML engineers deploying models to Apple devices
Alternatives & comparison
- Create ML
Apple's app and Swift framework for training image, text, sound, tabular and activity models on a Mac without writing training code, exporting directly to Core ML
ProprietaryFree - Foundation Models (Apple)
Apple's Swift framework giving apps access to the on-device Apple Intelligence language model with guided generation, tool calling and sessions, on OS 26 and later
ProprietaryFree - llama.cpp
C/C++ inference engine for LLMs and vision-language models with GGUF quantized weights, Metal, CUDA, Vulkan and other backends, a CLI and an OpenAI-compatible server
Open sourceOpen source - MLX
Apple's open-source array framework for machine learning on Apple Silicon, with NumPy-like Python, C++ and Swift APIs and unified CPU/GPU memory
Open sourceOpen source - PyTorch
Open-source deep-learning framework with eager tensors, autograd, torch.compile and distributed training, governed by the PyTorch Foundation and the base of most LLM tooling
Open sourceOpen source
Sources & verification
Primary sources consulted for this record. Claims are tied to the fields each source supports; the automated link checker re-verifies every URL on a schedule.
- Official documentationCore ML Tools guidechecked Nov 1, 2026
https://apple.github.io/coremltools/docs-guides
Supports: capabilities, data_formats, integrations
- Official documentationCore ML | Apple Developer Documentationchecked Nov 1, 2026
https://developer.apple.com/documentation/coreml
Supports: name, summary, capabilities, operating_systems
- Repositoryapple/coremltoolschecked Nov 1, 2026
https://github.com/apple/coremltools
Supports: license_spdx, source_model
license_spdx refers to coremltools; the Core ML framework itself is proprietary
- Confidence
- High
- Reviewed
- Nov 1, 2026
- Links
- Verified · Nov 2, 2026
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