Local Build Is Not Deployment

Your browser showing localhost proves one thing:

A local development server can serve a local build.

It does not prove the public site is deployed.

Local architecture

LOCAL SOURCE
   ↓
LOCAL JEKYLL BUILD
   ↓
LOCAL _site
   ↓
LOCAL DEV SERVER
   ↓
YOUR BROWSER

Production architecture

A GitHub Pages path adds repository/build/deployment infrastructure:

GIT COMMIT
   ↓ push
GITHUB REPOSITORY
   ↓ Pages publishing trigger
BUILD / WORKFLOW
   ↓
DEPLOYABLE PAGES ARTIFACT
   ↓
GITHUB PAGES
   ↓
PUBLIC URL

The exact workflow depends on whether you publish from a configured branch source or a custom GitHub Actions workflow.

New failure boundaries

Production adds:

• push/branch mistakes;
• workflow permission/configuration;
• dependency differences;
• production environment values;
• Pages source configuration;
• baseurl/URL assumptions;
• build/deploy job failures;
• caching/propagation delay.

Evidence before publishing

Record:

Local commit SHA:
Remote branch:
Expected Pages source/workflow:
Production URL:
Expected baseurl:

Checkpoint

Explain why "works on localhost" is useful evidence but cannot prove the deployment path is correct.