Video Caption App Development
Summary
Freelancer Client is hiring: Video Caption App Development.
Location: Remote
I have an existing mobile app project called CAPTION MASTER .
What you'll do:
• Logo and design assets if needed
• Preview the video with captions
• Review the Flutter app code
• Review the backend code
• Review the Figma design
• Provide a clear plan before implementation
• Complete or rebuild the backend
• Create stable API endpoints for the mobile app
Requirements:
• Monthly plan
• Yearly plan
• Free user limitations
• Premium access control
• Restore purchases
• Subscription status check
• Lock premium features behind subscription
• 5. Firebase / Authentication
Nice to have:
• RevenueCat integration
• Native Apple In-App Purchase and Google Play Billing
• Current mobile app appears to be Flutter.
• Backend currently appears to be Python/Flask.
• I am open to suggestions if you recommend a better backend approach, but please explain why.
Skills: Translation, Mobile App Development, Android, iOS Development, Backend Development, Flutter, Video Processing, Google Firebase, API Development
Budget: $30–$250 USD
Source: Freelancer Client via Remote / Online. Apply on the source website.
Original
I have an existing mobile app project called CAPTION MASTER .
The app is already designed in Figma and the mobile app code is partially ready. The project stopped before completing the backend, API integration, subscriptions, and final deployment.
The app is built for iOS and Android and is focused on short video captioning and translation.
Figma design is ready:
https://www.figma.com/file/RN6DD6qabDx9vzMY1dPG3L?node-id=0:1&locale=en&type=design
I will provide the existing project files, including:
* Flutter mobile app project
* Existing backend project
* Figma design
* Logo and design assets if needed
App Idea
CAPTION MASTER is a mobile app that allows users to:
* Import a video from their device
* Generate automatic captions/subtitles
* Translate captions into another language
* Edit caption text
* Choose caption style, font, color, and position
* Preview the video with captions
* Export the final video with burned-in captions
* Export subtitle files such as SRT if possible
* Save projects/drafts
* Access premium features through subscription
The target users are content creators for TikTok, Instagram Reels, YouTube Shorts, and social media videos.
Current Situation
The design is ready and the frontend is partially developed, but I need a professional developer to complete the technical side.
The missing or incomplete parts are:
1. Backend completion
2. API integration
3. Video upload and processing
4. Speech-to-text / transcription
5. Caption translation
6. Subtitle generation
7. Burn captions into video
8. Subscription system
9. User authentication if needed
10. Testing on iOS and Android
11. App Store / Google Play readiness
Existing Backend
There is an existing backend project using Python/Flask.
It appears to use:
* FFmpeg
* Faster Whisper / Whisper-based transcription
* Translation service
* Video/audio processing
* SRT subtitle generation
I need the developer to review the current backend and decide whether to continue using it, improve it, or rebuild the backend in a better production-ready way.
Required Work
I need you to complete the full app workflow:
1. Review Existing Code
* Review the Flutter app code
* Review the backend code
* Review the Figma design
* Identify what is already working and what is missing
* Provide a clear plan before implementation
2. Backend Development
* Complete or rebuild the backend
* Create stable API endpoints for the mobile app
* Handle video uploads securely
* Process video/audio using FFmpeg
* Generate captions using Whisper or another reliable speech-to-text API
* Translate captions into selected languages
* Return captions, SRT files, and processed video
* Add proper error handling
* Add logging
* Make the backend ready for production deployment
3. API Integration
* Connect the Flutter app to the backend
* Make the upload, caption generation, translation, preview, and export flow work properly
* Add loading states, progress states, and error messages
* Make sure the app works smoothly with real videos
4. Subscriptions / Payments
Please add a subscription system for iOS and Android.
Preferred solution:
* RevenueCat integration
or
* Native Apple In-App Purchase and Google Play Billing
Subscription requirements:
* Monthly plan
* Yearly plan
* Free user limitations
* Premium access control
* Restore purchases
* Subscription status check
* Lock premium features behind subscription
5. Firebase / Authentication
If needed, complete Firebase setup for:
* User login
* Anonymous login or email login
* Saving user projects
* Tracking premium status if required
If Firebase is already included in the project, please review and fix the setup.
6. Video Export
The app must be able to:
* Export final video with captions burned into the video
* Save/export video to the user’s device
* Export subtitle file if possible
* Keep good quality after export
7. Testing
Please test the app on:
* iPhone / iOS simulator and preferably real iPhone
* Android emulator and preferably real Android device
Testing should include:
* Upload video
* Generate captions
* Translate captions
* Edit captions
* Change caption style
* Export video
* Subscription purchase flow
* Restore purchase
* Error handling
8. Deployment Support
I need help preparing the app for:
* Apple App Store
* Google Play Store
Including:
* Build configuration
* Bundle ID / package name review
* App signing guidance
* Production backend URL setup
* Environment variables
* Final testing build
* TestFlight / internal testing if possible
Important Requirements
* The app must match the Figma design as closely as possible.
* The app must support both iOS and Android.
* The final code must be clean and organized.
* The backend must be secure and production-ready.
* API keys must not be exposed inside the mobile app.
* The app should be scalable and not just a local demo.
* The developer must explain what server/cloud hosting is needed.
* The developer must provide setup instructions after completion.
Preferred Tech
Current mobile app appears to be Flutter.
Backend currently appears to be Python/Flask.
I am open to suggestions if you recommend a better backend approach, but please explain why.
Possible services:
* OpenAI Whisper API
* Faster Whisper
* AssemblyAI
* Deepgram
* Google Cloud Speech
* OpenAI API for translation if suitable
* RevenueCat for subscriptions
* Firebase if needed
* AWS / Google Cloud / Render / Railway / DigitalOcean / VPS for hosting
Deliverables
At the end of the project, I expect:
1. Fully working Flutter iOS/Android app
2. Completed backend
3. API fully connected to the app
4. Subscription system working
5. Video captioning and translation workflow working
6. Video export working
7. Clean source code
8. Deployment instructions
9. Environment variable documentation
10. TestFlight / Android test build support
11. Clear explanation of how to run the app locally and in production
Location & Details
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