head to head · open source
cognee vs langchain4j
cognee has 30,780 GitHub stars, 3,050 forks, 495 open issues and last shipped yesterday. langchain4j has 13,116 stars, 2,555 forks, 878 open issues and last shipped 2 days ago. cognee leads on adoption by 135% (30,780 vs 13,116 stars). cognee is written in Python under Apache-2.0; langchain4j is written in Java under Apache-2.0. cognee has attracted 10% as many forks as stars, langchain4j 19%. cognee was the more recently maintained of the two, and both are self-hostable with no licence fee.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| cognee | langchain4j | |
|---|---|---|
| GitHub stars | ★ 31K | ★ 13K |
| License | Apache-2.0 | Apache-2.0 |
| Written in | Python | Java |
| Last push | 2026-09-17 | 2026-09-16 |
| Forks | ⑂ 3.0K | ⑂ 2.6K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick cognee if
- You weight community size — 31K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Python
- You value the larger contributor base for long-term maintenance
pick langchain4j if
- You want the langchain4j feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Java
- You evaluated both and langchain4j fits your workflow better
About cognee
Cognee is an open source AI memory platform for agents, released under the Apache 2.0 license and written in Python. It ingests data in any format and builds a self hosted knowledge graph that agents query to recall, connect, and act with full context across sessions. The project lives in the Python ecosystem, installs through standard package managers, and sits in the AI and machine learning infrastructure category alongside graph databases and context engineering tooling. A companion research paper, "Optimizing the Interface Between Knowledge Graphs and LLMs for Complex Reasoning" by Markovic et al., 2025, docu…
read the full cognee overview →
About langchain4j
LangChain4j is an Apache 2.0, open source, idiomatic Java library for building LLM powered applications on the JVM, aimed at Java developers and enterprise teams who want one unified API over many LLM providers and embedding stores without leaving the Java ecosystem.
read the full langchain4j overview →
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Frequently asked questions
Is cognee or langchain4j more popular?
cognee has 30,780 GitHub stars and langchain4j has 13,116. cognee has the larger community by that measure.
Are cognee and langchain4j free?
Both are open source. cognee is licensed under Apache-2.0 and langchain4j under Apache-2.0. Neither carries a licence fee.
What is the difference between cognee and langchain4j?
cognee is written in Python and langchain4j in Java. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, cognee or langchain4j?
Choose cognee if you want the larger community (30,780 stars) or its Apache-2.0 licence terms. Choose langchain4j if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.