Capacitor production builds retaining development server.url configuration

Context

Capacitor's server.url setting in capacitor.config.json directs the WebView to a local development server for live reload. The documentation marks this as a development-only feature, yet the CLI does not automatically remove or override the value when running capacitor build ios or capacitor build android. If the key remains, the packaged app attempts to load http://localhost:8100 on the device, resulting in a white screen or connection error with no actionable log output.

Constraints

• Plain JSON configuration files cannot express environment-dependent logic.
• No built-in CLI flag (e.g., --prod) strips server.url or server.cleartext during the sync or copy phases.
• Teams must maintain separate config files (capacitor.config.prod.json) or migrate to capacitor.config.ts with process.env.NODE_ENV checks, which adds a TypeScript compilation step.
• CI/CD pipelines frequently forget to swap configs, making this a recurring release-day failure.

Goal

Establish a reliable, low-maintenance strategy that guarantees server.url and server.cleartext are absent from production native projects without relying on manual steps or custom scripts that diverge across repositories.

• What patterns have proven effective for enforcing environment-specific Capacitor configuration across multiple platforms and CI providers?
• Does Capacitor 6.x introduce any native mechanism (hooks, env files, or config merging) that eliminates the need for duplicate config files?
• How can the server.cleartext flag be validated as disabled in production builds as part of an automated check?