AssetManifest.bin.json 404 in Preview Environment Only - Font Loading Broken Despite Previous Report Being Closed

[toponepercent247]

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

When publishing any FlutterFlow app to the preview environment (via "View Full Screen" button), the AssetManifest.bin.json file fails to load with a 404 error. This causes cascading font loading failures for all default FlutterFlow fonts (Outfit, PlusJakartaSans, ReadexPro, etc.). Text appears with fallback/system fonts or as empty spaces.

Critical Observations:

• Error occurs ONLY in Preview environment (preview.flutterflow.app)
• Test Mode/Run from editor works perfectly - no AssetManifest errors, fonts load correctly
• Both of my projects affected (requesta-client-app-34gsns and requesta-service-provider-winzpd)
• All browsers tested (Chrome, Edge, Firefox) show identical 404 errors
• Fresh publishes today still show the error
• Error started appearing on February 6, 2026 (~13:00 GMT+2)

Console Errors:
GET https://preview.flutterflow.app/requesta-client-app-34gsns/[project-id]/assets/AssetManifest.bin.json 404 (Not Found)

Error while trying to load an asset: Flutter Web engine failed to fetch "assets/AssetManifest.bin.json". HTTP request succeeded, but the server responded with HTTP status 404.

Error: google_fonts was unable to load font [Multiple Fonts] because the following exception occurred: Unable to load asset: "AssetManifest.bin.json".

Expected Behavior

• The FlutterFlow build pipeline should generate and deploy AssetManifest.bin.json to the preview environment
• All default fonts should load correctly in the Preview environment
• The Preview environment should function identically to Test Mode
• Applications should render with proper typography as configured in the FlutterFlow editor

Steps to Reproduce

1. Open either of my affected FlutterFlow projects (permission granted)
2. Click "Test/Run" to publish to preview environment
3. Click the "View Full Screen" button when compilation completes
4. Open browser DevTools (F12) → Console tab
5. Observe 404 error for AssetManifest.bin.json
6. Observe subsequent font loading failures for all default fonts

Critical Test Comparison:

• Test Mode (Run from editor): ✅ Works correctly, no errors
• Preview Environment (Full Screen): ❌ 404 error, fonts fail

Note: This issue cannot be reproduced from a blank project as it appears to be a platform-wide regression in the preview deployment pipeline.

Previous Report & Closure Issue

This issue was previously reported as [BUG] AssetManifest.bin.json 404 in Preview Environment - Font Loading Broken #6907 on February 6, 2026.

The issue was closed as a duplicate of #6887, but these are fundamentally different problems:

• My issue ([BUG] AssetManifest.bin.json 404 in Preview Environment - Font Loading Broken #6907): AssetManifest.bin.json 404 errors ONLY in Preview environment (Test Mode works)
• Issue Google Fonts not loading since latest Flutter upgrade #6887: AssetManifest.json font loading problems in Test/Run mode

The closure appears to have been incorrect as:

1. The error persists after the fix for Google Fonts not loading since latest Flutter upgrade #6887 was deployed
2. The error is environment-specific (Preview only)
3. Test Mode functions correctly, proving this is a preview deployment pipeline issue

Steps to Reproduce

No - the steps to reproduce above do NOT start from a blank project. This issue is specific to the preview environment deployment pipeline and affects existing projects.

Reproducible from Blank

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

Bug Report Code (Required)

IT4WhvHqz852rsMA7a6Jc8FFoDwXH1s7UI0/lcN9bEgjfJTrPaYPXfikSEpWZ9+kTHxcL2aKjnodw87ShYfuA+UrGE6Yb655yodcEhXgdzuXMITUOqWdPHJfL8VJJVyay5+rphVQPsFacXge2lOqJ968ZAXAHqLjDUcRIc+lDKnDo3uqQ0SLb3kNh1JWeC/v

Visual documentation

Environment

- **FlutterFlow version:** Latest version (22 Feb 2026)
- **Platform:** Web (FlutterFlow builder)
- **Browser name and version:** [Chrome Version 145.0.7632.76 (Official Build) (64-bit)]
- **Operating system and version affected:** [Windows 10]

Additional Information

Critical Impact on Development:

This issue has completely blocked our ability to use FlutterFlow effectively because:

1. Free tier functionality broken - Cannot properly test or demo applications
2. Location services require Preview - Test Mode doesn't support location services, which our mapping features require
3. Both projects affected - Proves this is platform-wide, not project-specific
4. Business validation blocked - Cannot demonstrate a preview of the app
5. Development workflow halted - Cannot validate if FlutterFlow meets production needs

Timeline:

• February 6, 2026 (13:00 GMT+2): Errors first appeared during testing
• February 6, 2026: Issue [BUG] AssetManifest.bin.json 404 in Preview Environment - Font Loading Broken #6907 reported
• February 9, 2026: Issue closed as duplicate of Google Fonts not loading since latest Flutter upgrade #6887
• February 10, 2026: Fresh publishes still show identical errors
• Current: Issue persists despite closure of related ticket

What makes this different from #6887:

Aspect	#6887 (Closed)	My Issue (#6907)
Environment	Test/Run mode	Preview only
Manifest file	AssetManifest.json	AssetManifest.bin.json
Test Mode	❌ Broken.	✅ Works perfectly.
Preview	Not tested	❌ 404 error
Root cause.	General font config	Preview deployment pipeline

What I've Tried:

• ✓ Fresh publishes of both projects (Feb 10, 2026)
• ✓ Multiple browsers (Chrome, Edge, Firefox)
• ✓ Incognito mode with extensions disabled
• ✓ Cleared cache and service workers
• ✓ Test Mode verification (works correctly)

Root Cause Suspected:
The FlutterFlow build pipeline is failing to generate or deploy AssetManifest.bin.json to the preview CDN specifically. This file is essential for Flutter web applications to locate and load assets/fonts. The fact that Test Mode works suggests the local build process is correct, but the preview deployment pipeline is broken.

Request:

1. Please reopen this issue as it is distinct from Google Fonts not loading since latest Flutter upgrade #6887
2. Investigate the preview deployment pipeline specifically
3. Compare the build artifacts between Test Mode and Preview environment
4. Verify that AssetManifest.bin.json is being generated and deployed to the correct path

This is a critical regression affecting free tier users' ability to evaluate and use FlutterFlow. The platform should provide basic functionality like font loading in the preview environment without errors.

This issue has created an insurmountable barrier to continued platform use

As a solo developer who has invested 2.5 years building on FlutterFlow since its introduction, this bug has made the platform completely unusable for my business needs.

My Context:

• 2.5 years of development - I've been building on FlutterFlow since the platform launched
• Solo founder/developer - No team, no stakeholders, just me investing countless hours daily time consumed
• External contracts in place - I now have agreements with external service providers I have committed with to service this app
• Ready to launch - As soon as the app is developed and ready we will launch, but cannot be properly tested
• Limited funds - As a solo developer, resources are tight. Upgrading to a paid plan makes sense IF the platform works
• Paid plan commitment - I am ready to upgrade to deploy to iOS App Store and Google Play Store simultaneously, but I cannot commit funds to a platform with broken core functionality

Why this is critical:

1. Location services require Preview mode - My app's core functionality (mapping, geolocation for service providers) cannot be tested in Test Mode. This is not optional - it's the foundation of my business.

2. 2.5 years of work cannot be validated - After years of development, I cannot properly test if the app functions as intended. Every hour invested is now in question.

3. External commitments at risk - I have contracts with external providers who are relying on this app. I cannot fulfil these commitments if I cannot test and validate the functionality.

4. Cannot justify paid subscription - I am ready and willing to upgrade to a paid plan to deploy to app stores. However, I cannot justify spending limited funds on a platform where the preview environment - essential for testing - is fundamentally broken.

5. Intellectual property exposure risk - I am forced to use the public GitHub issue tracker to report this bug, exposing my proprietary app concept, business logic, and 2.5 years of work to anyone with a GitHub account. This is completely unacceptable.

6. Development confidence destroyed - If core font loading is broken in Preview, what other deployment issues will emerge after I pay for a subscription?

The impact on my business:

• I cannot fulfill contracts with external providers
• 2.5 years of development may be rendered useless
• I cannot take the next step to become a paying customer
• I am forced to expose my intellectual property to the public
• My business launch is indefinitely delayed

Without an immediate fix, I have no choice but to abandon FlutterFlow after 2.5 years of investment. This is not hyperbole - the platform has become unusable for my business needs.

The Catch-22 I'm Facing:

• ✅ I want to upgrade to a paid plan
• ✅ I need to deploy to app stores (requires paid plan)
• ✅ I have external contracts ready
• ❌ I cannot test core functionality (Preview broken)
• ❌ I cannot justify paying for broken functionality
• ❌ My business is stuck in limbo

This is a make-or-break moment. I have invested years, secured external partnerships, and am ready to launch - but a platform bug with the preview environment is preventing me from moving forward. The preview environment is not a "nice-to-have" feature - it is essential for testing real-world functionality before committing to a paid subscription.

A platform that cannot reliably deploy its own preview environment cannot be trusted for production applications, and a solo developer with limited funds cannot risk paying for functionality that doesn't work.

Additionally, forcing free tier users to expose their intellectual property in public GitHub issues to report platform-breaking bugs is a serious flaw in FlutterFlow's support model. I should not have to choose between fixing broken functionality and protecting 2.5 years of trade secrets.

[Alezanello]

Hello!!

Just a quick reminder: Preview mode is not intended for testing core functionality. It does not compile the project or execute backend logic—it simply generates a visual preview of your app’s UI.

To properly test core features or business logic, please use Run Mode, Test Mode, or Local Run.

Because Preview doesn’t compile the app, it may not correctly process the assets manifest. For example, if you’re using custom fonts, they might not load as expected. This is a limitation of Preview mode, since it only provides a quick visual representation of your app without executing full logic.

I’ll confirm with the engineering team whether this is expected behavior or a bug. In the meantime, please use Run/Test/Local modes for any core functionality testing.

[toponepercent247]

@Alezanello

Thank you for the quick response and clarification about Preview mode's intended purpose. I understand that Preview mode has limitations, but I need to explain why this is still a critical blocker for me.

First, please compare these two preview links from the SAME project:

✅ Working Preview (February 5, 2026) - NO ERRORS, fonts load correctly:
https://preview.flutterflow.app/requesta-service-provider-winzpd/kPz7Uyc1G3pIM9YcUmw7

❌ Broken Preview (February 10, 2026) - AssetManifest.bin.json 404, fonts fail:
https://preview.flutterflow.app/requesta-service-provider-winzpd/yEhhU52qIxsIMziRse9I

Why Preview Mode is Essential for My Testing:

1. Location Services Requirement - My app's core functionality relies on geolocation and mapping features. As noted in FlutterFlow's documentation, Test Mode does NOT support location services. The "Run" button → "View Full Screen" preview is the ONLY way I can test:

   • Real-time location tracking for service providers
   • Map interactions and marker placements
   • Geolocation-based service matching

2. This Used to Work for 2.5 Years - Until February 6, 2026, Preview mode correctly displayed fonts and assets. The working Feb 5th link above proves that something changed in the deployment pipeline between Feb 5-6 that broke previously working functionality. I have been testing this way throughout 2.5 years of development.

3. Not "Just Visual" - While Preview may have limitations, font loading is a basic visual element that should work consistently. The AssetManifest.bin.json 404 error indicates a deployment pipeline issue, not a Preview mode limitation. Note that I am NOT using custom fonts - these are FlutterFlow's default fonts.

4. Compounding Issues - I have been unable to properly test my app since February 6 due to multiple blocking issues ([BUG] AssetManifest.bin.json 404 in Preview Environment - Font Loading Broken #6907, Custom Code Compilation Error Persists Even After Reverting to Original Working Code #6949, and now AssetManifest.bin.json 404 in Preview Environment Only - Font Loading Broken Despite Previous Report Being Closed #6950). Each day this remains broken delays my ability to validate my application.

The Business Reality I'm Facing:

After 2.5 years of development on FlutterFlow, I'm now stuck in an impossible situation:

• I cannot upgrade to a paid plan without verifying that my app's core location features work
• I cannot verify location features without the Preview mode (Run → Full Screen)
• I have external contracts and service providers waiting on this app
• Every day this remains broken delays my business launch

Our Commitment to FlutterFlow:

I want to be clear - my goal is NOT to abandon FlutterFlow. I have invested 2.5 years of work into this platform because I believe in it. As soon as these issues are resolved and I can complete my final testing:

✅ I will immediately upgrade to a paid plan
✅ I will deploy to iOS App Store and Google Play Store simultaneously
✅ I will launch my business that depends on this platform
✅ I will continue building on FlutterFlow for years to come

I'm raising these issues because I WANT to continue with FlutterFlow, not because I'm looking for reasons to leave. The work I've invested is too valuable to waste, and I'm committed to seeing this through - but I need the platform's core functionality to work as it did for the past 2.5 years.

What I'm Asking:

Could you please confirm with the engineering team:

1. Was there a change to the Preview deployment pipeline around February 5-6, 2026 that could explain why AssetManifest.bin.json stopped being generated? The two preview links above provide a clear before/after comparison.

2. Is there ANY alternative way for free tier users to test location-based features? Test Mode doesn't support location services, Local Run requires paid plans, and Preview is now broken.

3. If this is truly "expected behavior" for Preview mode, why did it work correctly for 2.5 years until February 6? And why does the Feb 5th link still work perfectly?

I'm asking for Preview mode to work the way it did for the past 2.5 years so I can validate that my app's core functionality works before I invest in a paid plan. I am working on this project single-handedly with no outside help and have limited funds, so I need to budget carefully before upgrading.

Thank you for understanding the urgency of my situation.

Ernest