Skip to content

Run/Test Mode fails to render app – “Null check operator used on a null value” in generated main.dart.js #7435

Description

@genaidreeves-ai

Can we access your project?

  • I give permission for members of the FlutterFlow team to access and test my project for the sole purpose of investigating this issue.

Current Behavior

My project renders correctly inside the FlutterFlow editor, but when I launch Run/Test Mode, the app does not render correctly. The WelcomeScreen begins loading and displays the Built Daily Fathers logo, but the remainder of the screen becomes a large gray area and the app does not proceed normally.

Chrome DevTools reports: “Null check operator used on a null value” with the stack trace pointing to the FlutterFlow-generated main.dart.js.

We have already reconnected the Firebase project, regenerated the Firebase configuration files, deployed the Firestore indexes, deployed Firebase/Firestore rules, and deployed the Private APIs. A completely new Run/Test build was then generated, but the same gray-screen/runtime failure remains.

The affected project is a SAFE TEST copy being used specifically to diagnose the problem without making destructive changes to the original application.

Expected Behavior

Run/Test Mode should render the WelcomeScreen exactly as it appears in the FlutterFlow editor, including the Start My Journey and Sign In buttons, and allow the user to continue through the application without a null-value runtime exception.

Steps to Reproduce

1.Open the Built Daily Fathers SAFE TEST project in FlutterFlow.
2.Open the WelcomeScreen. The page renders correctly inside the FlutterFlow editor.
3.Start a new Run/Test Mode session.
4.Wait for the application to load.
5.The Built Daily Fathers logo appears, but the remainder of the application becomes a large gray area and the WelcomeScreen does not finish rendering.
6.Open Chrome Developer Tools → Console.
7. The console reports: “Null check operator used on a null value” originating from the FlutterFlow-generated main.dart.js.
8. Generating a completely new Run/Test build produces the same result.

Reproducible from Blank

  • The steps to reproduce above start from a blank project.

Bug Report Code (Required)

ITwsls/l5YxItbxb7arUasZR/T0sKVggU403mMNxbAwgHOvzEokTe8nVN05AUsimSng/I0+Z8H8z16mKkOzpE/k3CxKsU6VEyKoJSgKVQm2uSpSWEpOKZUdDPMpEBWGP1Ku7kAhRKbFYR1o/7V+YNumRfB3AJrLYJGgCDuSYCKPPngurAB7vUSNZ+xcDGW2yD+QUTwbWncb/1P4Di7Cmuol8qBVXzoPSwtX1TBKTWVk=

Visual documentation

Image Image

Environment

FlutterFlow version: Current web version as of August 26, 2026
Platform: Web / FlutterFlow browser editor and Web Run/Test Mode
Browser name and version: Google Chrome 152
Operating system and version affected: macOS

Additional Information

This issue is blocking development and testing of the application. The pages render correctly inside the FlutterFlow editor, but Run/Test Mode fails during runtime and displays a large gray area. We have spent several hours troubleshooting the project, including checking page actions, navigation, Firebase configuration, Firestore indexes/rules, and generating completely new Run/Test sessions. The problem persists.

Chrome DevTools reports “Null check operator used on a null value” from the FlutterFlow-generated main.dart.js. We need assistance identifying the generated runtime failure without rebuilding the application again.

Metadata

Metadata

Assignees

No one assigned

    Labels

    status: needs triageA potential issue that has not been confirmed as a bug.

    Type

    No type

    Projects

    No projects

    Milestone

    No milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions