AccelOne modernized a personal safety app's backend and mobile app in two phases: replacing legacy infrastructure with Node.js and Express, migrating iOS to Swift 5, and building a dedicated media server for video processing. The result was a stable, scalable app with reliable video processing and steady new subscriptions.
Business Requirement
A personal safety app needed to regain market share and grow subscriptions. To do that, it needed a full overhaul of its outdated backend and mobile app.
The legacy architecture caused feature failures, high operational costs, and a poor user experience. This put the app's core promise, reliable protection, at risk. The client needed a modern, scalable, and stable solution to restore and improve its features.
Business Solution
AccelOne modernized and stabilized the app end to end. The work focused on updating the backend, improving the mobile app, and fixing video processing and sign-up. We delivered it in two phases:
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Partial mobile app update: Updated libraries and frameworks for both iOS and Android.
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Parallel backend creation: Built a Node.js + Express backend alongside the legacy system, using the same database.
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Feature restoration: Restored several app features. Video processing and sign-up issues remained.
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Complete backend rewrite: Rebuilt the backend fully in Node.js + Express with modern infrastructure.
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Media server creation: Built a Node.js media server to handle video processing.
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iOS app migration: Migrated the iOS app to Swift 5, updated libraries, and confirmed compatibility with the latest iPhones.
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Issue resolution: Fixed video and sign-up issues, rewriting most video sections for better performance.
Technical Solution
AccelOne's technical solution included:
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Backend development: Node.js + Express, with a modern infrastructure architecture.
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Media server: Node.js-based, for efficient video processing.
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iOS app migration: Migrated to Swift 5, updated libraries, confirmed compatibility with the latest iPhones.
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Crash and bug monitoring: Added to track app stability and performance across devices.
The dedicated team from AccelOne included:
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Senior iOS Engineer
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Senior Backend Engineer
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Technical Project Manager
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QA Engineer
Challenges
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Reverse engineering: The team had to review legacy code, plus extra components for the back-office website and events page, to rebuild the backend correctly.
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Legacy system compatibility: The new backend and media server had to work seamlessly with the existing database and systems.
Approach
AccelOne addressed these challenges by embedding our team with the client's internal team. We split the project into phases, each focused on a different part of the app and backend:
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Preparation: Built a full understanding of the app and identified critical points for testing and development.
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Development and testing: Updated and migrated app components, built the new backend and media server, and tested rigorously for stability and performance.
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Issue resolution and optimization: Fixed existing issues and optimized the app for a better user experience and more reliability.
Results
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Increased stability: The new app and backend are stable and scalable. Most of the old version's problems are gone.
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Enhanced video processing: The new media server makes video processing faster and always available.
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Feature reliability: All features work as expected, and the platform is gaining new subscriptions every week.
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Improved user experience: Users on the latest iPhones now get a much better experience thanks to the updates.
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Future-proofing: The codebase now runs on the latest languages and frameworks, with better support for modern mobile OS versions.
Conclusion
AccelOne's work with the personal safety app solved its critical business challenges. The result: more stability, more scalability, and happier users.
The app now delivers a reliable, seamless experience. It runs at lower operational cost and meets high standards for quality and security, setting the client up for long-term success.
Frequently asked questions
What backend technology did AccelOne use to modernize the personal safety app
AccelOne rebuilt the backend in Node.js and Express, replacing the legacy system with a modern, scalable infrastructure and a dedicated media server for video processing.
Why was the project split into two phases?
Phase one restored features using a parallel backend while keeping the same database, but video processing and sign-up issues remained. Phase two fully rewrote the backend and media server to resolve those issues.
Did AccelOne update the iOS app as well as the backend?
Yes. AccelOne migrated the iOS app to Swift 5, updated its libraries, and confirmed compatibility with the latest iPhone models.
What results did the personal safety app see after the rebuild?
The app gained a stable, scalable backend, faster and more reliable video processing, full feature reliability, a better experience on the latest iPhones, and consistent new subscriptions each week.