Improved Node.js Deployment Performance on Azure App Service

We’ve made significant improvements to how Node.js applications are deployed on Azure App Service — with deployment times now up to 8× faster in some cases.

Traditionally, the node_modules directory was extracted and synced in full during deployment. This process could be slow and resource-intensive, especially for apps with large dependency trees. To address this, we’ve optimized the way node_modules is handled.

What’s Changed?

During the deployment phase, instead of copying the entire node_modules folder to the site, we now compress it into a node_modules.tar.gz archive. This archive is placed under /home/site/wwwroot and is accompanied by a manifest file (oryx-manifest.toml) that provides instructions for what needs to happen during app startup.

When the application starts, the archive is extracted into /node_modules inside the runtime container. We then create a symbolic link from /home/site/wwwroot/node_modules to the extracted directory (/node_modules) so that the Node.js runtime can seamlessly locate the modules.

To ensure full compatibility, the /node_modules path is also appended to the environment’s PATH variable, allowing Node.js apps to access their dependencies without any changes to code or configuration.

Why This Matters

This approach significantly reduces the amount of data that needs to be synced during deployment, speeding up the process and improving reliability.

This change is part of our ongoing efforts to make Node.js apps faster and easier to run on Azure App Service. More improvements coming soon — stay tuned!