Deployment troubleshooting · September 25, 2026

How to fix a failed AI app deployment

When a project from Lovable, Bolt, Cursor, Claude Code or another AI coding tool fails to deploy, the last line in the log rarely explains the cause. Start with the first specific error, match it to the checks below, then run the production build again.

Start with the first specific error

A message such as “command exited with code 1” only says that the build failed. Scroll upward to the first specific error, note its file, package or setting, and fix that before chasing later messages. Vercel’s troubleshooting guide recommends checking the lines before the generic failure and running the production build locally.

Check your build log

Paste a redacted build log to identify common patterns and get a short list of checks. The text is analyzed in your browser and is not uploaded or saved.

Paste the failed build log

Only common build errors are recognized. This is a first check, not a complete code review.

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Analysis runs in this browser and the text is not saved or uploaded. Remove API keys, passwords, tokens and private URLs before pasting logs.

How this checker works

Find the first useful clue.

It looks for common build failures such as missing packages, environment settings, TypeScript errors and output folders.
It runs on this page. No AI service or hosting account is connected.
It does not change your project. Review the suggested checks and confirm them in your code and host settings.

Deploying a Lovable project to Vercel? Check the current version requirement and setup guide.

Common errors and what to check

“Missing script: build”

Open package.json and inspect the scripts section. Either add the correct build script for the project or change the hosting Build Command to the command it already defines. Run it from the project root to confirm it works.

“Module not found” or “Could not resolve”

Check the import path letter by letter, confirm the file was committed, and make sure any package is listed in the project dependencies. A project that works on one computer can still fail on a case-sensitive build system if the import capitalization differs from the filename.

“Missing environment variable” or an undefined value

Add the named variable to the hosting dashboard for the environment that failed, then start a new deployment. Keep private keys out of client-side code and source control. Redact values before sharing a build log.

Unsupported Node.js version or engine

Read the version requirement in the error and choose a compatible Node.js runtime in the hosting project settings. Align the local and hosted versions, then rebuild.

Output or publish directory not found

Check where the framework actually writes its build files and set the host’s output directory to match. The right setting depends on the framework; server-rendered apps should use the matching framework preset instead of a static output folder.

“window is not defined” or “document is not defined”

The build is running browser-only code in a server context. Find the file in the first error, then move that code into the framework’s client-only component or execution path.

Compare three launch paths

Host	Best fit	Check first
Vercel	Next.js and frontend apps with Git-based preview and production deployments.	Hobby is for personal, non-commercial use. A business or revenue-generating project needs a commercial plan.
Hostinger	Managed Node.js apps deployed from GitHub, including supported Next.js projects.	Node.js apps require an eligible Business Web or Cloud plan. Promotional prices and renewal prices differ.
DigitalOcean App Platform	Apps that need a service, worker or database alongside a frontend.	Static sites have a free tier; app containers start at $5/month. Database and bandwidth costs can be separate.

Provider facts checked September 25, 2026. Prices and terms change; use the linked provider pages for current details.

Once the build works, choose a suitable host

Personal Next.js demo

Vercel is a straightforward fit for a personal project. Its Hobby plan is not for commercial use, so revisit the plan before adding paid features or running a business.

Node.js app with GitHub code

Hostinger offers managed Node.js deployment from GitHub on eligible Business Web and Cloud plans. Read the plan and build requirements before moving a site.

App with backend services

DigitalOcean App Platform can run app components from a repository. Estimate the container, database and outbound transfer together.

Check these before connecting a domain

Push the generated project to a private GitHub repository if it contains unfinished work or secrets.
Remove API keys from source files and configure them in the hosting provider’s environment settings.
Confirm the production build and start command work from the repository.
Check database access rules, backups and the provider plan’s commercial-use terms.
Estimate every production service, including database, storage and outbound data transfer.

Official provider references

Use the hosting finder for a starting recommendation, then confirm the details directly with the provider.

Percent to Prompts is independent and does not currently earn commission from these providers.