Developer Guide

Using Vespa Cloud for development is easy—all you need is to register as a tenant in the Vespa Cloud console, and then build and upload your application package.

See getting started to deploy a basic sample application to Vespa Cloud, or its Java variant to deploy an application with custom Java components.

Keep reading for more details on how to develop applications using Vespa Cloud, including basic terminology, tips on using the console UI, and how to benchmark and size your application before going to production.

Manual deployments

Developers will typically deploy their application to the dev zone during development. Each deployment is owned by a tenant, and each specified instance is a separate copy of the application; this lets developers work on independent copies of the same application, or collaborate on a shared one, as they prefer—more details here. These values can be set in the Vespa Cloud UI when deploying, or with each of the build and deploy tools, as shown in the respective getting-started guides. Additionally, a deployment may specify a different zone to deploy to, instead of the default dev zone; see performance testing below for how to do this.

Auto downsizing

Deployments to dev are downscaled to one small node by default, so that applications can be deployed there without changing services.xml. If you need more resources in the dev application, set nodes or resources explicitly by adding those tags to services.xml with deploy:environment="dev", see variants in services.xml.


The dev zone is not for production serving, and has no uptime guarantees.

An automated Vespa software upgrade can be triggered at any time, and this may lead to some downtime if you have only one node per cluster (as with the default auto downsizing).

Performance testing

In addition to dev, there is also a perf zone for performance testing. Like production zones, this zone honors the resources specified in services.xml—see the reference for how to configure them. Performance and sizing tests can then be extrapolated to a production scenario. In all other ways, this zone works the same way as dev.

To deploy to perf with Vespa CLI:


To deploy to perf with Maven:

-D environment=perf

Read more in benchmarking.

Debugging Java Components

Vespa Cloud does not allow debugging over the Java Debug Wire Protocol (JDWP) due to the protocol's inherent lack of security measures. If you need interactive debugging consider deploying your application to a self-hosted Vespa installation and manually add the JDWP agent to JVM options.

You may debug your Java code by requesting either a JVM heap dump or a Java Flight Recorder recording through the Vespa Cloud Console. Go to your application's cluster overview and select export JVM artifact on any container node. The process will take up to a few minutes. You'll find the steps to download the dump on the Console once it's completed. Extract the files from the downloaded Zstandard-compressed archive, and use the free JDK Mission Control utility to inspect the dump/recording.

Generate JVM dump

Tips and troubleshooting

  • Vespa Cloud upgrades daily, and applications in dev and perf also have their Vespa platform upgraded. This usually happens at the opposite time of day of when deployments are made to each instance, and takes some minutes. Deployments without redundancy will be unavailable during the upgrade.

  • Failure to deploy, due to authentication (HTTP code 401) or authorization (HTTP code 403), is most often due to wrong configuration of tenant and/or application, when using command line tools to deploy. Ensure the values set with Vespa CLI or in pom.xml match what is configured in the UI. For Maven, also see here for details.

  • In case of data plane failure, remember to copy the public certificate to src/main/application/security/clients.pem before building and deploying. This is handled by the Vespa CLI vespa auth cert command.

  • To run Java system and staging tests in an IDE, ensure all API and data plane keys and certificates are configured in the IDE as well; not all IDEs pick up all settings from pom.xml correctly: