Phi is Microsoft's family of compact open models designed for efficient local and edge deployment. Phi-4 is the current generation.
Microsoft introduced Phi-1 and Phi-2 to demonstrate how carefully curated and synthetic training data can make small models unusually capable. Phi-3 expanded the family for mobile and multimodal use. The Phi-4 generation includes a 14B general model and reasoning variants, plus smaller and multimodal checkpoints. Phi models are released under the MIT license and are designed for research, local inference, and resource-constrained production workloads.