Jamba Reasoning 3B
AI21 Labs · 2025-10-08 · 3.2B parameters
Jamba Reasoning 3B is AI21 Labs' compact open-weight reasoning model, publicly released on October 8, 2025. Its 3,197,109,632-parameter checkpoint uses a 28-layer hybrid Transformer–Mamba architecture with 26 Mamba layers and two MQA attention layers, and is configured for a 262,144-token context; AI21 separately reports that the model can handle up to 1 million tokens. Intended for edge and on-device inference, its published training stages include large-scale pretraining, approximately 0.5 trillion tokens of math-and-code mid-training, SFT, DPO, and RLVR for reasoning, tool use, instruction following, code generation, mathematics, structured output, and information extraction.