Microsoft — Foundation Models Platform

Microsoft Phi is a family of small language models designed for resource efficiency without compromising performance. Starting with Phi-2 (2.7B parameters) that surpassed Mistral and Llama-2 models at 7B-13B parameters, the Phi family now includes Phi-4, Phi-4-multimodal (text, audio, vision), and Phi-4-mini. Phi-4 costs USD 0.13 per 1M input tokens and USD 0.50 per 1M output tokens on Azure, with a blended rate of USD 0.22 per 1M tokens. The models excel at math and reasoning tasks, with Phi-4 outperforming comparable and larger models through high-quality synthetic datasets and post-training innovations. Phi models are particularly effective for resource-constrained environments, on-device inference, latency-sensitive scenarios, and cost-constrained use cases. Available through Azure AI Foundry with pay-as-you-go and provisioned throughput options, Phi models provide a 200,000-word vocabulary in 20+ languages. While impressive for their size, limitations include primary English design, reduced factual knowledge capacity, code generation primarily in Python, and tendency for textbook-like verbose responses.