1. VelocityDB：
它是.NET对象数据库，可以嵌入/分发并扩展为图形数据模型(VelocityGraph)。数据库速度快，内存消耗低。它是一种极高性能，易于使用，可伸缩，可嵌入和可分发的对象数据库系统。
2. XAP：
它是用于任务关键型应用程序的高性能内存数据网格，并提供一组基本的数据存储功能，例如事务，索引和查询语言(类似于SQL的查询)。它是用于安装和分发应用程序软件的文件格式。
VelocityDB和XAP之间的区别：
| VelocityDB | XAP |
|---|---|
| It is developed by VelocityDB Inc and initially released on 2011. | It is developed by Gigaspaces Technologies and initially released on 2000. |
| Its server operating systems of VelocityDB is Any that supports .NET | Its server operating systems of XAP Linux, macOS, Solaris, Windows. |
| Its primary database model is Graph DBMS and Object oriented DBMS | Its primary database model is Document store and Key-value store. |
| Absence of Secondary database models in VelocityDB | Secondary database models of XAP is Object oriented DBMS. |
| It supports .Net programming languages. | It supports .Net, C++, Java programming languages. |
| APIs and other access methods of VelocityDB is .Net | It supports GigaSpaces LRMI, Hibernate, JCache, JDBC, JPA, ODBC, RESTful HTTP API, Spring Data. |
| It has Data Schema. | Data Schema of XAP is schema-free. |
| It has Implementation language-C# . | Implementation language of XAP is Java, C++, .Net. |
| It has transaction concepts is ACID (atomicity, Consistency, Isolation, and Durability). | XAP has ACID (atomicity, Consistency, Isolation, and Durability) concepts transaction concepts. |
| Absence of Replication methods | Replication methods of XAP- Master-master replication and Master-slave replication. |
| It has Immediate Consistency concept. | It has Immediate Consistency concept. |
| Sharding is a Partitioning methods of VelocityDB. | Sharding is a Partitioning methods of XAP. |