Neo4j 3.x introduced the concept of user-defined procedures and functions.Those are custom implementations of certain functionality, that can’t be (easily) expressed in Cypher itself.They are implemented in Java and can be easily deployed into your Neo4j instance, and then be called from Cypher directly.

The APOC library consists of many (about 450) procedures and functions to help with many different tasks in areas like data integration, graph algorithms or data conversion.

APOC Full can be installed withNeo4j Desktop, after creating your database, by going to theManage screen, and then thePlugins tab.ClickInstall in the APOC box and wait until you see a green check mark near "APOC".

Please provide feedback and report bugs asGitHub issues or join theNeo4j Community Forum and ask with the APOC tag.

User definedFunctions can be used inany expression or predicate, just like built-in functions.

Procedures can be called stand-alone withCALL procedure.name();

But you can also integrate them into your Cypher statements which makes them so much more powerful.

All included procedures are listed in theoverview in the documentation and detailed in subsequent sections.

See theAPOC User Guide for documentation of each of the major features of the library, including data import/export, graph refactoring, data conversion, and more.

To call procedures correctly, you need to know their parameter names, types and positions.And for YIELDing their results, you have to know the output column names and types.

INFO:The signatures are shown in error messages, if you use a procedure incorrectly.

You can see the procedures signature in the output ofCALL apoc.help("name")

The signature is alwaysname : : TYPE, so in this case:

Since APOC relies on Neo4j’s internal APIs you need to use thematching APOC version for your Neo4j installaton.Make sure that thefirst two version numbers match between Neo4j and APOC.

Go tothe latest release forNeo4j version 4.4 and download the binary jar to place into your$NEO4J_HOME/plugins folder.

You can findall releases here.