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Semantic Kernel

Microsoft's AI orchestration SDK for .NET, Python, and Java

open sourceupdated Apr 21, 2026

Microsoft's open-source AI SDK that lets you combine AI models with conventional programming. Supports plugins, planners, memory, and function calling with availability for .NET, Python, and Java. Designed for enterprise developers building AI-powered applications within the Microsoft ecosystem, offering deep integration with Azure AI services and existing business logic.

Semantic Kernel is an open-source SDK from Microsoft that enables developers to integrate cutting-edge LLM technology into their applications using C#, Python, and Java. It solves the challenge of building AI-powered enterprise applications by providing a lightweight, extensible framework for orchestrating AI plugins, managing memory, and executing multi-step plans with support for OpenAI, Azure OpenAI, Hugging Face, and other model providers. Semantic Kernel serves as the production foundation of the Microsoft Agent Framework, offering battle-tested reliability for enterprise AI deployments across the Azure ecosystem.

Semantic Kernel provides a robust plugin ecosystem supporting native code functions, prompt templates, OpenAPI specifications, and Model Context Protocol (MCP) integrations, giving agents access to virtually any external capability. Its Agent Framework, now generally available, enables building modular AI agents with tools, memory, and sophisticated planning capabilities where the AI model breaks down complex tasks into executable steps through automatic function calling. The built-in Process Framework models complex business processes with state management, while vector database support through Azure Cognitive Search, Pinecone, and Chroma enables semantic search and long-term agent memory.

Semantic Kernel is designed for enterprise developers, .NET teams, and organizations building production AI applications within the Microsoft and Azure ecosystem. It integrates deeply with Azure AI services, Microsoft 365, Dynamics 365, and the broader Microsoft stack, making it the natural choice for enterprises already invested in Microsoft infrastructure. As part of the Microsoft Agent Framework alongside AutoGen, Semantic Kernel provides the stability and production readiness needed for large-scale agent deployments, with official support, extensive documentation, and a growing community of enterprise contributors.

Pricing

Free, open-source

Platforms

Python, .NET, Java

Categories

Tags

Use Cases

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LangChain

Framework for LLM applications

The most widely-used framework for building LLM-powered applications, available in Python and JavaScript. Provides abstractions for chains, agents, RAG, memory, tool usage, and structured output. Integrates with 100+ LLM providers, vector stores, document loaders, and tools. LangSmith offers tracing and evaluation. LangGraph enables stateful, multi-agent workflows with cycles. 100K+ GitHub stars. The de facto standard for LLM application development despite growing alternatives like LlamaIndex.

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Haystack

NLP and RAG pipeline framework by deepset

Haystack is an open-source AI orchestration framework by deepset for building production-ready LLM applications with explicit control over retrieval, routing, memory, and generation pipelines. Its component-based architecture lets developers chain specialized pieces into branching, looping pipelines for semantic search, RAG, QA, and autonomous agents. Integrates with OpenAI, Anthropic, Mistral, Cohere, Hugging Face, Azure, AWS Bedrock, and major vector stores.

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Data framework for LLM applications

Leading Python framework for building LLM-powered applications with focus on data-aware and agentic workflows. Provides tools for RAG (Retrieval-Augmented Generation), document indexing, vector store integrations, query engines, and multi-agent orchestration. 150+ data connectors for various sources. Works with OpenAI, Anthropic, local models, and more. Includes LlamaHub for community tools and LlamaCloud for managed RAG pipelines. 50K+ GitHub stars.

Open Source

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Comparisons

FAQ

What is Semantic Kernel?

Microsoft's open-source AI SDK that lets you combine AI models with conventional programming. Supports plugins, planners, memory, and function calling with availability for .NET, Python, and Java. Designed for enterprise developers building AI-powered applications within the Microsoft ecosystem, offering deep integration with Azure AI services and existing business logic.

Is Semantic Kernel free?

Yes — Semantic Kernel is open source and free to use. Free, open-source

Is Semantic Kernel open source?

Yes — Semantic Kernel is open source.

What are the best Semantic Kernel alternatives?

The top editor-verified Semantic Kernel alternatives are LangChain, Haystack, LlamaIndex.