Compare the Top AI Agent Builders as of November 2025

What are AI Agent Builders?

AI agent builders are tools, platforms, or frameworks designed to create, train, and deploy intelligent virtual agents capable of performing tasks autonomously. These builders provide resources for natural language processing, decision-making algorithms, and machine learning, enabling agents to interact with users effectively. They often include user-friendly interfaces or APIs to customize behaviors, integrate with existing systems, and adapt to specific use cases. AI agent builders are widely used across industries, including customer service, healthcare, education, and entertainment, to enhance efficiency and user experience. By leveraging these tools, developers and businesses can rapidly create sophisticated agents tailored to their unique needs. Compare and read user reviews of the best AI Agent Builders currently available using the table below. This list is updated regularly.

  • 1
    Cognee

    Cognee

    Cognee

    ​Cognee is an open source AI memory engine that transforms raw data into structured knowledge graphs, enhancing the accuracy and contextual understanding of AI agents. It supports various data types, including unstructured text, media files, PDFs, and tables, and integrates seamlessly with several data sources. Cognee employs modular ECL pipelines to process and organize data, enabling AI agents to retrieve relevant information efficiently. It is compatible with vector and graph databases and supports LLM frameworks like OpenAI, LlamaIndex, and LangChain. Key features include customizable storage options, RDF-based ontologies for smart data structuring, and the ability to run on-premises, ensuring data privacy and compliance. Cognee's distributed system is scalable, capable of handling large volumes of data, and is designed to reduce AI hallucinations by providing AI agents with a coherent and interconnected data landscape.
    Starting Price: $25 per month
  • 2
    Letta

    Letta

    Letta

    Create, deploy, and manage your agents at scale with Letta. Build production applications backed by agent microservices with REST APIs. Letta adds memory to your LLM services to give them advanced reasoning capabilities and transparent long-term memory (powered by MemGPT). We believe that programming agents start with programming memory. Built by the researchers behind MemGPT, introduces self-managed memory for LLMs. Expose the entire sequence of tool calls, reasoning, and decisions that explain agent outputs, right from Letta's Agent Development Environment (ADE). Most systems are built on frameworks that stop at prototyping. Letta' is built by systems engineers for production at scale so the agents you create can increase in utility over time. Interrogate the system, debug your agents, and fine-tune their outputs, all without succumbing to black box services built by Closed AI megacorps.
    Starting Price: Free
  • 3
    LlamaIndex

    LlamaIndex

    LlamaIndex

    LlamaIndex is a “data framework” to help you build LLM apps. Connect semi-structured data from API's like Slack, Salesforce, Notion, etc. LlamaIndex is a simple, flexible data framework for connecting custom data sources to large language models. LlamaIndex provides the key tools to augment your LLM applications with data. Connect your existing data sources and data formats (API's, PDF's, documents, SQL, etc.) to use with a large language model application. Store and index your data for different use cases. Integrate with downstream vector store and database providers. LlamaIndex provides a query interface that accepts any input prompt over your data and returns a knowledge-augmented response. Connect unstructured sources such as documents, raw text files, PDF's, videos, images, etc. Easily integrate structured data sources from Excel, SQL, etc. Provides ways to structure your data (indices, graphs) so that this data can be easily used with LLMs.
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