Skip to content
aicoolies logo
Ray logo

Ray

Distributed AI compute engine for scaling Python and ML workloads

Ray is an open-source distributed computing framework built for scaling AI and Python applications from a laptop to thousands of GPUs. It provides libraries for distributed training, hyperparameter tuning, model serving, reinforcement learning, and data processing under a single unified API. Ray's public site highlights OpenAI and other enterprise users. Maintained by Anyscale with Apache-2.0 open-source licensing.

About Ray

Ray has emerged as the foundational compute engine behind many of the world's most demanding AI workloads, with Ray public materials highlighting OpenAI and other enterprise users. Developed originally at UC Berkeley's RISELab and now maintained by Anyscale, the framework provides a deceptively simple Python-first API that uses decorators like @ray.remote to parallelize arbitrary functions and classes across distributed clusters without rewriting application logic.

The framework's library ecosystem addresses every stage of the ML lifecycle. Ray Train handles distributed model training with native PyTorch and TensorFlow integration, Ray Tune provides distributed hyperparameter optimization with support for grid search, Bayesian optimization, and population-based training, Ray Serve enables scalable model deployment with independent scaling and fractional GPU allocation, and Ray Data offers streaming data processing for feature engineering and batch inference. RLlib remains the industry standard for production reinforcement learning at scale.

Ray is designed for high-throughput distributed task and actor workloads, but teams should validate workload-specific latency and throughput rather than treating public positioning as a benchmark. Its actor model supports stateful computation essential for parameter servers and iterative training algorithms, while heterogeneous compute management lets teams mix CPUs and GPUs within a single pipeline to maximize hardware utilization. Clusters can autoscale dynamically and deploy on Kubernetes, AWS, GCP, Azure, or bare metal, with KubeRay providing the standard Kubernetes operator for production deployments.

Pricing & Platform Specs

Pricing Summary

Ray is a free and open-source distributed computing framework governed by the PyTorch Foundation under the Apache 2.0 license. It can be self-hosted on any cloud or on-prem cluster with zero licensing costs, while managed execution is available via cloud providers like Anyscale.

Supported Platforms

Python, Linux, macOS, Windows, Kubernetes, major clouds

Explore categories, tags & use cases

Alternatives

All Ray alternatives →

Serverless GPU compute platform for AI inference and training

Modal is a serverless compute platform that lets developers run AI workloads on GPUs with a Python-first SDK. Functions deploy with decorators, auto-scale from zero to thousands of containers, and bill per second. It supports LLM inference, fine-tuning, batch jobs, and sandboxes, with current GPU options including B200, H200, H100, A100, L40S, A10, L4, and T4. Modal’s 2026 Series C valued the company at $4.65B.

freemium

Unified framework for fine-tuning 100+ large language models

LLaMA-Factory is an open-source toolkit providing a unified interface for fine-tuning over 100 LLMs and vision-language models. It supports SFT, RLHF with PPO and DPO, LoRA and QLoRA for memory-efficient training, and continuous pre-training. The LLaMA Board web UI enables no-code configuration, while CLI and YAML workflows serve advanced users. Integrates with Hugging Face, ModelScope, vLLM, and SGLang for model deployment.

Open Source

Side-by-Side Comparisons

Ray logo
Ray
vs
Modal logo
Modal

Ray vs Modal — Open-Source Cluster Framework vs Serverless GPU Platform

Ray and Modal both solve GPU compute scaling for AI workloads but represent fundamentally different infrastructure philosophies. Ray is an open-source distributed computing framework that orchestrates workloads across self-managed or cloud clusters, while Modal is a serverless platform that abstracts infrastructure entirely behind a Python SDK with per-second billing and automatic scaling from zero to thousands of GPUs.

Community experience

Sources & verification

Sources checked
Content verified

Verification dates are editorial checks. Routine CMS saves and automatic updatedAt timestamps do not advance them.

FAQ

What is Ray?

Ray is an open-source distributed computing framework built for scaling AI and Python applications from a laptop to thousands of GPUs. It provides libraries for distributed training, hyperparameter tuning, model serving, reinforcement learning, and data processing under a single unified API. Ray's public site highlights OpenAI and other enterprise users. Maintained by Anyscale with Apache-2.0 open-source licensing.

Is Ray free?

Ray offers a free tier alongside paid plans. Ray is a free and open-source distributed computing framework governed by the PyTorch Foundation under the Apache 2.0 license. It can be self-hosted on any cloud or on-prem cluster with zero licensing costs, while managed execution is available via cloud providers like Anyscale.

Is Ray open source?

Yes — Ray is open source.

Is Ray still maintained?

Yes — Ray is active. Its listing was last verified on August 26, 2026.

What are the best Ray alternatives?

The first editor-selected Ray alternatives are Modal, LLaMA-Factory.

How does Ray score in our review?

The published editorial review lists Ray at 92/100 overall across speed, privacy, and developer experience. Check the review's evidence status and test metadata for its verification level.