Transformers v5: Simple model definitions powering the AI ecosystem

Back to Articles Transformers v5: Simple model definitions powering the AI ecosystem Published December 1, 2025 Update on GitHub Upvote 297 +291 Lysandre lysandre Follow Arthur Zucker ArthurZ Follow Cyril Vallez cyrilvallez Follow Vaibhav Srivastav reach-vb Follow Transformers' version v4.0.0rc-1, the initial release candidate for version 4, was released on November 19th, 2020. Five years later, we now release v5.0.0rc-0. Today, as we launch v5, Transformers is installed more than 3 million times each day via pip - up from 20,000/day in v4 🤯. Altogether, it has now surpassed 1.2 billion installs! The ecosystem has expanded from 40 model architectures in v4 to over 400 today, and the community has contributed more than 750,000 model checkpoints on the Hub compatible with Transformers, up from roughly 1,000 at the time of v4. This growth is powered by the evolution of the field and the now mainstream access to AI. As a leading model-definition library in the ecosystem, we need to continuously evolve and adapt the library to continue being relevant. Reinvention is key for longevity in AI. We’re fortunate to collaborate with many libraries and apps built on transformers, in no specific order: llama.cpp, MLX, onnxruntime, Jan, LMStudio, vLLM, SGLang, Unsloth, LlamaFactory, dLLM, MaxText, TensorRT, Argmax, among many other friends. For v5, we wanted to work on several notable aspects: simplicity, training, inference, and production. We detail the work that went into them in this...