Hy4 preview vs Keras: Features, Pricing & Which Is Better (2026)
A side-by-side comparison of Hy4 preview and Keras — features, pricing, and ideal use cases — to help you decide which AI tool fits your workflow.
Hy4 preview
Tencent
Tencent's open-weight Hy4 preview, a 770B-parameter Mixture-of-Experts model with 49B active parameters and a 1M-token context window.
Key features
- 770B Mixture-of-Experts Architecture: Holds 770 billion total parameters while activating only 49 billion per token, so capacity scales without proportional inference cost.
- 1M-Token Context Window: Accepts inputs exceeding one million tokens, allowing whole codebases, long document sets or extended agent traces in a single prompt.
- Apache 2.0 Open Weights: Released under a permissive licence that allows commercial use, modification and redistribution with no separate agreement.
- Productivity Task Focus: Tuned for real-world coding, office work and scientific research rather than narrow benchmark optimisation.
- Multi-Product Availability: Accessible globally through Tencent's WorkBuddy, CodeBuddy, Yuanbao and ima applications in addition to the raw weights.
- API Access via TokenHub and OpenRouter: Can be called through Tencent Cloud TokenHub or OpenRouter for teams that prefer hosted inference over self-hosting.
Best for
- Whole-Repository Code Work: Load an entire codebase into the million-token context to reason about refactors and cross-file dependencies at once.
- Long-Horizon Agent Tasks: Drive multi-step agent workflows where the full history of tool calls and intermediate results must stay in context.
- Self-Hosted Deployment: Run a frontier-scale open-weight model on private infrastructure where data cannot leave the organisation.
- Scientific Literature Analysis: Ingest large collections of papers or experimental logs and synthesise findings without chunking the input.
- Office Document Processing: Summarise, draft and restructure long reports, contracts and spreadsheets in enterprise workflows.
- Commercial Fine-Tuning: Adapt the weights for a proprietary product under the Apache 2.0 licence without negotiating a model licence.
Keras
Keras Team
High-level, user-friendly deep learning API for building, training, and deploying models across TensorFlow, JAX, and PyTorch.
Key features
- Multi-Backend Support: Run Keras models on TensorFlow, JAX, or PyTorch by selecting the backend before importing, enabling portability and the ability to leverage different runtimes and accelerators (including XLA).
- High-Level APIs: Offers Sequential, Functional, and Subclassing APIs for building models quickly and expressively, simplifying prototyping while supporting advanced model architectures.
- Pretrained Model Hub (keras-hub): A curated collection of canonical pretrained models (LLMs, vision, diffusion, segmentation, etc.) with easy one-line loading and generation APIs, enabling rapid transfer learning and inference.
- Interoperable Serialization: Saves models in .keras format (zip of config and weights) and supports framework-agnostic serialization to move models between backends without costly migrations.
- First-Party Extensions: Official libraries like KerasCV and KerasNLP provide industry-strength computer vision and NLP components that work natively across backends and integrate seamlessly with core Keras objects.
- Training Utilities and Callbacks: Rich training loop features including built-in optimizers, metrics, callbacks, and support for custom training steps to streamline experimentation and production training workflows.
- Hugging Face Hub Integration: Direct load/save integration with the Hugging Face Hub using huggingface_hub client, making model sharing, versioning, and discovery straightforward.
- Hardware Acceleration and Optimization: Leverages backend-specific performance features (e.g., JAX with XLA compilation) to accelerate training and inference on modern accelerators.
- High-level model APIs: Sequential, Functional, and Model subclassing for flexible model construction
- Multi-backend support: runs on TensorFlow, JAX, or PyTorch (selectable via KERAS_BACKEND before import)
- Ecosystem integration: keras-hub (pretrained models), KerasCV, KerasNLP, keras-tuner for extended workflows
- Model IO and serialization: .keras format (zip of config + weights), standard save/load utilities
- Training utilities: built-in losses, metrics, optimizers, callbacks, custom training loops and fit/evaluate/predict workflows
- Interoperability: models and components can be trained/serialized in one backend and reused in another
- Hugging Face Hub integration: push/pull models directly using huggingface_hub client
- Extensible layers and metrics: modular components for research and production
- Support for large models and LLM workflows: tokenizers, generate APIs in Keras model implementations (via keras-hub)
Best for
- Research Prototyping: Rapidly design and iterate on novel neural network architectures using Keras's high-level APIs and quickly switch backends to evaluate performance trade-offs.
- Transfer Learning and Fine-Tuning: Load pretrained models from keras-hub for tasks like image classification, segmentation, or language understanding, then fine-tune on domain-specific data.
- Production Model Deployment: Train with one backend (e.g., TensorFlow) and export models in interoperable formats or use the preferred runtime backend for deployment to match infrastructure requirements.
- Computer Vision Workflows: Use KerasCV components for building, training, and evaluating state-of-the-art vision models (detection, segmentation, generative models) with reusable pipelines.
- NLP and LLM Inference: Consume pretrained language models from keras-hub (including Llama3 presets) with string-based generation APIs and tokenizers included for end-to-end text generation.
- Education and Tutorials: Teach deep learning concepts with a readable, concise API that lowers the barrier to entry for students and practitioners learning model fundamentals.
- Hub-Based Collaboration: Share, version, and load models directly to/from the Hugging Face Hub to enable reproducible experiments and community collaboration.
- Rapid prototyping and experimentation of neural network architectures
- Training and fine-tuning pretrained models for vision (KerasCV) and NLP (KerasNLP)
- Hyperparameter search and optimization using keras-tuner
- Exporting and sharing models via keras-hub or Hugging Face Hub
- Research-to-production workflows requiring portability across TensorFlow, JAX, and PyTorch