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Checks

Is your live site serving a development build?

By Mark KashefPublished October 8, 2026

This check flags a page that loads a script or library build meant for development, such as a dev server client or a development copy of a framework. Live sites should serve the production build.

What does this check look at?

It looks at whether a page loads a script or library build meant for development rather than production. It usually means the deploy ran the dev command or copied the wrong folder.

Pulse and Deep scans both run it. It applies only when the development signals analyser is on, as it is by default.

Curious what your site shows from outside? The quick check is free and needs no account.

Check it

What does a result mean?

What the report showsWhat it meansWhat to do
Low findingA development asset is declared on the page.Fix the deploy so it builds and serves production output.

The development asset is never run, so no access to a development server is shown. A clean result means nothing was found in what the scan read. It does not prove the problem is absent from parts the scan never sees.

How serious is a finding?

Treat this as a hardening gap. It makes an attacker’s job easier but gives them no path of its own, so fix it after anything more direct. Confidence starts at medium, because it rests on a pattern in your content. The report lists what to fix by how directly someone could use it, not by the severity label.

What does a confirmed finding have to show?

PartFor this check
Where it startsAnyone on the internet, with no account, cookie or credential
The protection that should stop itPublic deployments should serve the intended production artifacts
What is reachedA declared development client or library artifact
What followsExtra debug code or development behavior; no access is demonstrated

Fix it with your AI

The fix is almost always in the build or start command your host runs.

Fix prompt for any coding agent
My live site loads a development build asset: [paste the evidence from the report]. Check my hosting build settings and package.json scripts. Make sure the host runs the production build command (for example npm run build) and serves its output with the production start command, not the dev server. Remove any development-only client script from the HTML. Show me the settings to change.

How to check

Say Atlas, our example app at atlas.example, was deployed by running its dev server on a small cloud machine. The check sees the dev client script in the homepage and flags it.

Run a Pulse scan from your Lockpick account to see it for your site. Pulse or Deep explains what each scan reads, and the full list of checks shows the rest.

Questions people ask

Is a development build dangerous?

It is slower and can expose extra debugging behaviour. The check does not show access to a development server, only that a development asset is served.

How did this happen if my site looks normal?

Development builds look the same to visitors. They are bigger, slower and include tools meant only for your own machine.

See what your site shows from outside

A quick check reads your homepage the way a visitor would and gives you a score. No account needed.

Check your site

Related pages

  • Do your scripts point to a source map?
  • Does your site show error details or stack traces to the public?
  • Does your server announce its software version to everyone?

Sources

  1. How we rate findings Lockpick docs, read on October 7, 2026

About the author

Mark Kashef, Founder of Lockpick

I'm Mark, and I build Lockpick. I write these pages, and each one is checked against its sources before it goes live. The Updated date changes only when the page itself does.

Lockpick
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Lockpick is a security scanner for vibe-coded apps. It checks what your live site exposes and what a GitHub repo or AI skill would do before you install it, then gives you a fix prompt for Lovable, Bolt, Replit, Cursor or Claude Code.

Lockpick assesses public pages you are authorized to test, and public GitHub code it never runs.

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