What is wrangler.jsonc file in 0.email codebase?

In this article, we will review What is wrangler.jsonc file in 0.email codebase? We will look at:

1. wrangler.jsonc file in 0.email

2. start script in package.json

3. What is Wrangler? 

wrangler.jsonc file in 0.email

So at zero/apps/mail/wrangler.jsonc, you will find the below code:

{
  "$schema": "node_modules/wrangler/config-schema.json",
  "name": "zero",
  "compatibility_date": "2025-05-01",
  "compatibility_flags": ["nodejs_compat"],
  "main": "./worker.ts",
  "observability": {
    "enabled": true,
  },
  "env": {
    "local": {
      "vars": {
        "VITE_PUBLIC_BACKEND_URL": "http://localhost:8787",
        "VITE_PUBLIC_APP_URL": "http://localhost:3000",
      },
    },
    "staging": {
      "vars": {
        "VITE_PUBLIC_BACKEND_URL": "https://sapi.0.email",
        "VITE_PUBLIC_APP_URL": "https://staging.0.email",
      },
    },
    "production": {
      "vars": {
        "VITE_PUBLIC_BACKEND_URL": "https://api.0.email",
        "VITE_PUBLIC_APP_URL": "https://0.email",
      },
    },
  },
}

start script in package.json

In zero/apps/mail/package.json, you will find the below script:

"start": "wrangler dev --port 3000 --show-interactive-dev-session=false",

Here, Wrangler is used to start this 0.mail frontend.

"types": "wrangler types",
"deploy": "wrangler deploy",

Similarly, there is also a script for types and deploy.

What is Wrangler?

Wrangler, the Cloudflare Developer Platform command-line interface (CLI), allows you to manage Worker projects.

• API : A set of programmatic APIs that can be integrated with local Cloudflare Workers-related workflows.

• Bundling : Review Wrangler’s default bundling.

• Commands : Create, develop, and deploy your Cloudflare Workers with Wrangler commands.

• Configuration : Use a configuration file to customize the development and deployment setup for your Worker project and other Developer Platform products.

• Custom builds : Customize how your code is compiled, before being processed by Wrangler.

• Deprecations : The differences between Wrangler versions, specifically deprecations and breaking changes.

• Environments : Use environments to create different configurations for the same Worker application.

• Install/Update Wrangler : Get started by installing Wrangler, and update to newer versions by following this guide.

• Migrations : Review migration guides for specific versions of Wrangler.

• System environment variables : Local environment variables that can change Wrangler’s behavior.

Configuration

Wrangler optionally uses a configuration file to customize the development and deployment setup for a Worker.

It is best practice to treat Wrangler’s configuration file as the source of truth for configuring a Worker.

Read more about Wrangler configuration

About me

Hey, my name is Ramu Narasinga. I study codebase architecture in large open-source projects.

Email: ramu.narasinga@gmail.com

Build Shadcn CLI from scratch.

References:

1. https://github.com/Mail-0/Zero/blob/staging/apps/mail/wrangler.jsonc

2. https://github.com/Mail-0/Zero/blob/staging/apps/mail/package.json#L9

3. https://developers.cloudflare.com/workers/wrangler/configuration/

4. https://developers.cloudflare.com/workers/wrangler/