The Ultimate Checklist for When .env Variables Don’t Load in Vue 3 + Vite

Environment variables in Vue 3 + Vite should “just work,” yet many developers encounter confusing issues such as:

• Variables defined in .env not appearing in import.meta.env
• Incorrect values embedded during production builds
• Local development works, but deployed environments fail
• Environment-specific overrides (.env.production, .env.staging) not loading

This guide is a complete, SEO-optimized, practical checklist to diagnose and fix the most common causes of environment variables not working in Vite. If your .env values aren’t showing up, go through this list step by step.

Essential Vite Rules You Must Know

Key points every developer should remember

• Vite only exposes environment variables prefixed with VITE_ to the client.
• .env files are loaded once at startup, so Vite must be restarted after any changes.
• Vite injects environment variables at build time, not at runtime.

Understanding these fundamentals eliminates many common points of confusion.

The Prefix Problem (The #1 Cause)

What happens

If you write:

API_URL=https://example.com

…Vite will not expose it to the browser. You will get undefined when reading:

import.meta.env.API_URL

Why?

For security reasons, Vite exposes only variables that start with VITE_.

The fix

• Rename client-side variables to include the prefix:
  VITE_API_URL=https://example.com
• Access it as:
  import.meta.env.VITE_API_URL

Double-check:

• Every exported key starts with VITE_
• No typos like VITE_API_UR
• No trailing spaces or invisible characters

File Locations and Environment Modes

Incorrect file placement

.env files must be in the project root.
If they are inside src/ or another subdirectory, Vite will ignore them.

Mode-based loading (very important for builds)

Vite loads different files depending on the current mode:

• vite dev → .env + .env.development
• vite build → .env + .env.production
• vite build --mode staging → .env + .env.staging

What to check

• Are you using a custom mode (--mode) in CI?
• Does your build log show the correct mode?
• Are the contents of .env.production correct?

Server Restart and Cache Issues

Why Vite must be restarted

.env values are injected at startup.
Editing the file while dev server is running does not reload them.

Always restart after adding or modifying environment variables.

Cache issues

Occasionally Vite’s internal cache can keep stale values:

rm -rf node_modules/.vite
npm run dev

If problems persist:

rm -rf node_modules
npm install

Verify What Vite Actually Loaded

Always check with a console log

console.log(import.meta.env);
console.log(import.meta.env.VITE_API_URL);

If the key does not appear in the logged object, Vite isn’t reading it.
Re-check file names, paths, and prefixes.

TypeScript-Specific Issues (Missing Types)

Symptoms

• Autocomplete doesn’t show your environment variable
• Type errors occur when accessing custom variables

Solution

Create or update env.d.ts:

/// <reference types="vite/client" />

interface ImportMetaEnv {
  readonly VITE_API_URL: string;
}

Also verify:

• include in tsconfig.json covers env.d.ts
• No conflicting type settings inside the project

Mixing Up process.env and import.meta.env

A common mistake

Developers coming from Node.js often try:

process.env.VITE_API_URL

But in Vite client-side code, this will not work.

Use:

import.meta.env.VITE_API_URL

Vite does not emulate Node’s runtime environment variable system.

Files That Vite Does Not Process

Where Vite injects variables

import.meta.env is only available in files processed by Vite’s ESM pipeline.

The following may fail:

• Scripts placed in the project root
• Non-ESM modules
• Files outside src/

Fixes

• Move the script to src/
• Ensure it is loaded as an ES module
• Make sure Vite processes the file

Deployment Considerations (Netlify, Vercel, Cloudflare Pages, etc.)

Important: hosting platforms do not automatically load .env.production

You must configure environment variables in each provider’s dashboard.

For client-side usage, keys must include the prefix VITE_.

Check for:

• Missing variables in the hosting provider dashboard
• Incorrect variable values (accidental whitespace is common)
• CI pipelines that override .env values

Docker and Container Build Issues

Common pitfalls

• .env is not copied into the build container
• ARG or ENV is not passed during the build
• Multi-stage builds lose environment data

Tips

• Use --build-arg to inject values
• Confirm the final build stage contains the expected variables

Extra Troubleshooting Tips

Invisible formatting issues

• Leading/trailing spaces
• Full-width characters (common in copy-pasted text)
• UTF-8 with BOM causing unexpected first-character artifacts

Naming issues

Avoid variable names with:

• Hyphens (-)
• Dots (.)

Prefer:

VITE_API_URL
VITE_FEATURE_FLAG

Quick Step-By-Step Debugging Flow

1. Ensure .env is in the project root
2. Confirm all client variables start with VITE_
3. Restart Vite completely
4. Log import.meta.env to inspect loaded values
5. Check for typos or whitespace
6. Verify mode: dev / production / staging
7. Rebuild after deleting cache
8. Confirm environment variables in deployment platform
9. For TypeScript, ensure proper type definitions
10. For Docker, pass build args correctly

Pro tip

Add a temporary flag:

VITE_DEBUG=true

Then:

if (import.meta.env.VITE_DEBUG) {
  console.log(import.meta.env);
}

This quickly reveals incorrect values.

Final Thoughts

Environment variables in Vite are powerful but often misunderstood due to its strict, security-oriented design. By following this checklist, you can resolve nearly every case where .env values don’t load in Vue 3 + Vite.

If you want, I can also create:

• A shorter “copy-paste-ready” version for engineering wikis
• A troubleshooting flowchart
• A Cloudflare Pages / Netlify / Vercel-specific version