Phi 4 Reasoning Plus

Name: Phi 4 Reasoning Plus
Author: Microsoft Research

Released

2025-01-01

Last refreshed

2026-06-04

Status

Researched 92d ago

Open sourceCommercial use: permittedLong context

Phi 4 Reasoning Plus is worth evaluating for long context when its provider route and context window match the workload.

Use it for

Teams evaluating long context
Workloads that can use a 128k context window
Buyers comparing 2 tracked provider routes

Do not use it for

Vision or document-understanding workloads
Strict JSON or tool-calling flows

Specifications

Family: Phi-4
Released: 2025-01-01
Context: 128k
Parameters: 14B
Architecture: Decoder Only
Knowledge cutoff: 2025-03
Specialization: reasoning
Openness: Open source
License: MITOSI-approvedCommercial use: permitted
Weights: Unknown
Code: Unknown
Training: Pretrained

Created by

Microsoft Research

Advancing the state-of-the-art in AI and computing.

Redmond, Washington, United States

Founded 1991

Website

Pricing

Output / 1M

$0.500

Input / 1M

$0.125

Cheapest of 2 routes · Microsoft Foundry

Providers(2)

Fireworks AI Microsoft Foundry

View 2 provider routes

About

Phi 4 Reasoning Plus is Microsoft Research's Phi-4 model focused on step-by-step reasoning. It offers a 128K-token context window with weights openly available for self-hosting and scores 68.9 on GPQA.

Top use-case fit

Long context

Included by capability and metadata signals in the decision map.

Provider price ladder

Compare all 2

Compare API pricing across 2 providers for input and output tokens, batch, and cached reads when available.

Provider	Input / 1M	Output / 1M	Route
Microsoft Foundry	$0.125	$0.500	Serverless
Fireworks AI	$0.500	$0.500	Serverless

Available via routers & gateways(6)

LiteLLM

Gateway

Open-source Python SDK and proxy server that unifies 100+ LLM APIs behind a single OpenAI-compatible interface, with load balancing, cost tracking, and configurable failover.

Free OSSMicrosoft Foundry

OpenRouter

Hybrid

Unified hybrid gateway to 400+ models from 60+ providers via a single OpenAI-compatible API, with optional auto-routing that selects the best model per prompt.

PassthroughFireworks AI

Portkey

Gateway

Production AI gateway routing to 1,600+ LLMs with failover, load balancing, semantic caching, and guardrails; Apache 2.0 core is fully self-hostable with the complete feature set.

SubscriptionMicrosoft Foundry

Azure AI Foundry Model Router

Router

Microsoft Azure AI Foundry's native model router that uses a trained ML model to route each prompt in real time to the optimal Azure-hosted model, with Balanced/Cost/Quality mode selection and automatic failover.

PassthroughMicrosoft Foundry

Helicone

Gateway

Observability-first AI gateway with routing, caching, rate limiting, and request tracing; Apache 2.0 open-source core with a managed hosted tier for logging and analytics.

SubscriptionMicrosoft Foundry

Kong AI Gateway

Gateway

Multi-LLM AI gateway built on Kong Gateway 3.x, adding semantic routing, load balancing, guardrails, and MCP traffic analytics as plugins over Kong's existing API management platform.

SubscriptionMicrosoft Foundry

Capabilities

Reasoning

Benchmark peer barsfor Long context

No task-mapped benchmark peers are available for this model yet.

Benchmark scores(1)

Scores are benchmark-specific and are direction-aware: the same numeric gap can mean very different outcomes across suites. Use the leaderboard context and this model's provider route to decide whether the winning margin is meaningful for your workload.