serverless-esbuild VS serverless-analyze-bundle-plugin

Support Yarn PnP with externals bundling #327

We use serverless-esbuild to transpile our TypeScript code to JavaScript.

You should use appropriate tools to bundle your Lambda functions with a minimal size. For example, the Serverless Framework, with the serverless-esbuild plugin, automatically bundles your code and uploads it to AWS.

One of the most important aspects of serverless development is keeping an eye on your bundle sizes and to reduce cold start times on Lambda. Keeping this in mind, the template utilizes serverless-esbuild and serverless-analyze-bundle-plugin to provide function analysis out-of-the-box. I opted for serverless-esbuild over serverless-bundle for a few reasons:

Its faster and easier to setup that webpack and drastically reduces the size of the archive. For Serverless framework users there is https://github.com/floydspace/serverless-esbuild and if you use SAM CLI, you already get this for free since they now use esbuild in the build process

if you can, try using https://github.com/floydspace/serverless-esbuild - esbuild is stupid fast and it produces tiny artifacts. Its dead simple too compared to the webpacks/rollups/etc.

Note that there is one minor drawback, though: Kysely will add 120KB in your Lambdas bundles (props to for serverless-analyze-bundle-plugin for helping me out with this 🙌). It is not a lot, but not negligible either as NodeJS Lambdas bundles above 5MB negatively impacts their cold starts. So you might want to re-evaluate adding Kysely to your bundles if your query is not changing often.

There are plenty of tools out there to optimize the size of your bundles. For instance the Serverless Analyze Bundle Plugin integrates with the Serverless Framework and helps you diagnose which of your NodeJS dependency is not properly tree-shaked.

One of the most important aspects of serverless development is keeping an eye on your bundle sizes and to reduce cold start times on Lambda. Keeping this in mind, the template utilizes serverless-esbuild and serverless-analyze-bundle-plugin to provide function analysis out-of-the-box. I opted for serverless-esbuild over serverless-bundle for a few reasons: