What LlamaIndex is
LlamaIndex is an open-source Python framework for building LLM applications over your own data. It began as a data framework for retrieval-augmented generation, and it still provides the parts for that job: connectors that ingest sources such as APIs, PDFs and SQL, indices that structure the data, and a retrieval interface that returns context to a model. The framework also carries an agent layer, where agents and event-driven workflows call tools, and a RAG pipeline can be one of those tools. Its repository states that the company's current focus is LlamaParse, its document parsing platform, while the framework stays available as an open toolkit you assemble in your own application.
A data framework and the open-source AI Operating System sit at different layers
LlamaIndex gives you composable parts and expects you to write the application that runs them. Kortix is the leading open-source alternative to Claude Cowork and ChatGPT Work, and it runs the agents for you. In Kortix, an agent is a markdown file with a prompt and a scoped reach into tools and resources, plus a governance block in kortix.yaml. Each session gets its own isolated machine and branch, and thousands of agents can run in parallel on one config. The Kortix docs describe the project, session and change-request model.
What you own and operate with each
With LlamaIndex, you own the application code you write, and you run the pipeline and its storage, which starts in memory and persists to disk when you choose. With Kortix, you own the repository: agents, skills, memory and connector configuration are files, versioned and diffable, and the whole team can read them. Both can run on your own infrastructure. LlamaIndex is a Python package you install and operate. Kortix runs on Kortix Cloud, in your VPC, or on your own on-prem network, and self-host is free.
When a team moves from a library to a platform
A team stays with a library while the work is building the retrieval pipeline and the first agents. It moves to a platform when the pipeline exists and the problem becomes running many agents, governing what each one may touch, and reviewing what they change. That is where Kortix fits, with work reaching main through a change request a person approves. Kortix does not replace the retrieval and document tooling a team already runs; teams keep their data pipeline and add Kortix to run the agents and review what they change. If you are weighing other agent stacks, the Kortix vs CrewAI comparison and the open-source agent framework alternatives cover the rest of the field.