Foxx Microservices

ArangoDB allows application developers to write their data access and domain logic as microservices running directly within the database with native access to in-memory data. The Foxx microservice framework makes it easy to extend ArangoDB’s own REST API with custom HTTP endpoints using modern JavaScript running on the same V8 engine you know from Node.js and the Google Chrome web browser.

Unlike traditional approaches to storing logic in the database (like stored procedures), these microservices can be written as regular structured JavaScript applications that can be easily distributed and version controlled. Depending on your project’s needs Foxx can be used to build anything from optimized REST endpoints performing complex data access to entire standalone applications running directly inside the database.

If you’re coming from another JavaScript environment like Node.js this is similar to running multiple Node.js processes behind a load balancer: you should not rely on server-side state (other than the database itself) between different requests as there is no way of making sure consecutive requests will be handled in the same context.

Because the JavaScript code is running inside the database another difference is that all Foxx and ArangoDB APIs are purely synchronous and should be considered blocking. This is especially important for transactions, which in ArangoDB can execute arbitrary code but may have to lock entire collections (effectively preventing any data to be written) until the code has completed.

Compatibility caveats

While ArangoDB provides a lot of compatibility code to support code written for Node.js, some Node.js built-in modules can not be provided by ArangoDB. For a closer look at the Node.js modules ArangoDB does or does not provide check out the .

When using bundled node modules keep in mind that these restrictions not only apply to the modules themselves but also the node dependencies of those modules. As a rule of thumb: