langchain4j/langchain4j

Vector Databases

LangChain4j is an open-source Java library that simplifies the integration of LLMs into Java applications through a unified API, providing access to popular LLMs and vector databases. It makes implementing RAG, tool calling (including support for MCP), and agents easy. LangChain4j integrates seamlessly with various enterprise Java frameworks.

GitHub →Website →

8.1

GitHub Metrics

Stars

12.2k

Forks

2.3k

Open Issues

762

Watchers

115

Contributors

414

Weekly Commits

Language

Java

License

Apache-2.0

Last Commit

Jun 3, 2026

Created

Jun 20, 2023

Latest Release

1.15.1

Release Date

May 28, 2026

Synced: Jun 3, 2026

Quality Scores

Documentation Qualityw: 20%

8.6

Has docs site (https://docs.langchain4j.dev). Description: 344 chars. Stars signal: 12,189. Contributors: 414. Score: 8.6/10

Community Healthw: 20%

8.2

Stars: 12,189. Contributors: 414. Watchers: 115. Forks: 2,280. Issue ratio: 6.3%. Score: 8.2/10

Maintenance Velocityw: 15%

7.6

Last commit: 0d ago. Weekly commits: 0. Latest release: 1.15.1. Maturity bonus: 3.0y old. Score: 7.6/10

API Design & DXw: 20%

7.4

Stars/issues ratio: 16. Typed language: Java. Has documentation site. Permissive license: Apache-2.0. Popularity signal: 12,189 stars. Score: 7.4/10

Production Readinessw: 15%

8.3

Battle-tested: 12,189 stars. Peer review: 414 contributors. Versioned: 1.15.1. Licensed: Apache-2.0. Age: 3.0 years. Maintenance: last commit 0d ago. Score: 8.3/10

Ecosystem Integrationw: 10%

8.6

Fork interest: 2,280. Major ecosystem: Java. Integration-friendly: Apache-2.0. Adoption: 12,189 stars. Has web presence. Score: 8.6/10