Deeplearning4j vs Ludwig

Deeplearning4j is an open-source framework for building, training, and deploying neural networks on the JVM, using Java or Scala. It can compute on CPUs through OpenBLAS and oneDNN, or use CUDA for GPU acceleration. For distributed training, it supports Apache Spark across CPU or GPU clusters. The framework can import models from Keras, TensorFlow, and ONNX, while Python4J provides Python interoperability from Java through CPython embedding. Its wider ecosystem includes ND4J, SameDiff, DataVec, Keras Import, Python4J, OmniHub, and Arbiter. Documented deployment targets include JVM microservices, mobile devices, IoT, and Spark environments. The libraries are licensed under Apache License 2.0 and governed by the Eclipse Foundation. The quickstart recommends Maven for Java projects, with Ivy and Gradle also workable. Documentation covers version 1.0.0-M2.1. The free plan is listed at free. Support options include GitHub issues, community forums, Stack Overflow, and professional support from Konduit.

Ludwig is an open-source deep learning framework for building, fine-tuning, and deploying models across data types including tabular, text, image, audio, time series, and geospatial data. Users describe preprocessing, model components, training, and hyperparameter optimization in a validated YAML configuration instead of writing training loops. It supports multimodal and multi-task models, plus LLM fine-tuning methods including SFT, DPO, KTO, ORPO, and GRPO, with parameter-efficient options such as LoRA and QLoRA. Training can scale through Ray using DDP, FSDP, or DeepSpeed; Kubernetes and KubeRay are also listed. Hyperparameter optimization integrates Ray Tune and Optuna, with SQLite or PostgreSQL persistence. Models can be served as REST APIs or exported to SafeTensors, ONNX, or torch.export. The framework also offers experiment tracking integrations, generated reports and visualizations, and explainability features. Ludwig is free under the Apache 2.0 License, supports Python, and runs on Linux, macOS, Windows, or self-hosted infrastructure. The FAQ notes that Unsloth may be faster for users focused only on LLM fine-tuning and maximum throughput.