5 Common Mistakes When Deploying with Vercel and How to Avoid Them

Deploying your web app with Vercel can feel like a breeze, but even seasoned developers can hit snags. In 2026, with so many updates and features, it’s easy to overlook some key aspects that can lead to deployment headaches. Let's dive into five common mistakes we’ve made (and seen others make) when deploying with Vercel, and how you can avoid them.

1. Ignoring Build Configuration

What it Actually Means

Vercel allows you to configure your builds through a vercel.json file, which can dictate how your app behaves during deployment. Skipping this step or misconfiguring it can lead to unexpected results.

Our Take

We once deployed an app without properly setting our build output directory, resulting in a failed deployment. Always double-check your configuration!

Actionable Steps

• Create a vercel.json file in your project root.
• Specify the build command and output directory explicitly.

2. Not Leveraging Environment Variables

Why It Matters

Environment variables are crucial for managing different configurations for development, staging, and production. Failing to set these correctly can expose sensitive data or lead to app failures.

Limitations

Vercel provides a straightforward UI for managing environment variables, but it’s easy to forget to set them for different environments.

Our Experience

We launched a feature that relied on an API key that wasn’t set in production, causing a 404 error for users. Now, we always double-check our environment variables before deploying.

Quick Fix

• Set environment variables in the Vercel dashboard under Settings > Environment Variables.
• Use .env files in local development and ensure they are mirrored in Vercel.

3. Overlooking Performance Optimizations

Performance Implications

Vercel optimizes performance out of the box, but it’s still easy to overlook things like image optimization and caching strategies.

Our Experience

We once deployed a site with unoptimized images, which slowed down our load times significantly. Using Vercel’s built-in image optimization tools, we were able to reduce load times dramatically.

Actionable Steps

• Use the <Image /> component from Next.js for automatic image optimization.
• Leverage Vercel's caching strategies to improve load times.

4. Failing to Monitor Deployment Logs

The Importance of Logs

Deployment logs can provide invaluable insights into what went wrong during the deployment process. Ignoring them can lead to unresolved issues that impact your users.

Honest Limitations

While Vercel provides logs, they can sometimes be cryptic, especially for beginners.

Our Take

We’ve learned the hard way that ignoring logs can lead to repeated mistakes. We now make it a habit to review logs after each deployment.

Quick Fix

• Access logs from the Vercel dashboard under the Deployments tab.
• Set up alerts for failed deployments to catch issues early.

5. Not Testing Before Deployment

Why It’s Crucial

Testing your application before deployment is essential to ensure everything works as expected. Skipping this step can lead to broken features and frustrated users.

Our Experience

We once deployed a version of our app without adequate testing, which resulted in a major bug that made it unusable for several hours. Now, we have a strict testing protocol before each deployment.

Actionable Steps

• Implement a testing framework like Jest or Cypress.
• Run tests locally and in CI/CD pipelines before deploying to Vercel.

Conclusion: Start Here

To avoid these common pitfalls when deploying with Vercel, make sure you’re configuring your builds correctly, managing environment variables, optimizing performance, monitoring logs, and testing thoroughly.

If you're just starting out, focus on establishing a solid testing and configuration process. This will save you time and headaches in the long run.

What We Actually Use

In our stack, we rely heavily on Vercel’s built-in features, alongside tools like Jest for testing and Cloudinary for image optimization. If you’re looking to streamline your deployment process, start with these practices.