This Week in Neo4j: Langchain, Knowledge Graph, Cypher, Graph Data Science and more

Alexander Erdl

Senior Developer Marketing Manager

Thomas Orth

Welcome to This Week in Neo4j, your fix for news from the world of graph databases!

This edition empowers Java developers to build GraphRAG systems with LangChain4j, shows how to turn Product Hunt data into enriched Knowledge Graphs, introduces native conditional logic in Cypher 25 and reveals how Graph Data Science can untangle payment behaviour in complex supplier networks.

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Happy Graphing,

Alexander Erdl

 

COMING UP!

Thomas works on using and incorporating Generative AI to accelerate operations at Lockheed Martin

Connect with him on LinkedIn.

Joakim is a Featured NODES 2025 Speaker. His session is “Leveraging Knowledge Graphs and LLMs to document large scale codebases”. He will show how Lockheed Martin uses Knowledge Graphs and Generative AI to automate software architecture documentation, reducing errors and improving maintainability.


Thomas Orth

 

LangChain: Integrating Neo4j With LangChain4j for GraphRAG Vector Stores and Retrievers


Giuseppe Villani walks Java developers through integrating LangChain4j with Neo4j to build advanced, graph-based question-answering systems. LangChain4j introduces key components like Neo4jEmbeddingStore for storing vector embeddings and Neo4jText2CypherRetriever for generating and executing Cypher queries from natural-language inputs – enabling rich GraphRAG workflows directly in Java applications.

 

Knowledge Graph: Extracting Enriched Product Knowledge Graphs from Product Hunt into Neo4j


This Hypermode tutorial walks you through creating a Hypermode Agent that scrapes Product Hunt for trending products, enriches that data with LinkedIn insights and constructs a knowledge graph stored in Neo4j. It covers everything from configuring your Neo4j connection and agent behaviour to generating Cypher queries that insert nodes like Product, Person, Company, and Category, as well as matching relationships.

 

Cypher: Cypher Conditional Queries


Christoffer Bergman gives an overview of the native support for conditional queries, which was added in Cypher 25. This update enables developers to write cleaner, more readable logic, such as conditional branch execution and sequential query flows using UNION, WHEN and NEXT. Previously, achieving similar behaviour involved APOC procedures, correlated subqueries, or FOREACH hacks, which are now greatly simplified with the native Cypher syntax.

 

Graph Data Science: Navigating Payment Behavior Using Graph Data Science


In this article, Saswati Rao demonstrates how Neo4j’s Graph Data Science library can uncover hidden community clusters within complex supply networks. By mapping dependencies, such as suppliers’ links and external disruptions (like floods or tariff changes), onto a graph, she reveals how delays cascade through partner networks to affect payment behaviours.

 

 

POST OF THE WEEK: Mr. Dr. Eigenadmin

Watch my Letta agent build a knowledge graph from some blog posts. Uses neo4j through an MCP server + Letta Desktop.

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— Mr. Dr. Eigenadmin (@cameron.pfiffer.org) 12. August 2025 um 02:59



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