Senior Full-Stack Mobile and Backend Developer

About the Role
We are looking for an experienced Senior Full-Stack Mobile & Backend Developer to take technical ownership of two established mobile application platforms.
This is a hands-on engineering role with responsibility across mobile application development, backend systems, third-party integrations, cloud infrastructure, security, deployment and ongoing maintenance.
You will oversee the technical health, stability and continued development of both platforms, working across Flutter, PHP/Symfony, Firebase and AWS environments.
The successful candidate will be comfortable operating independently, troubleshooting complex technical issues, managing releases and ensuring both applications remain secure, reliable and scalable.
All client communication and project management will be handled internally by our team, allowing you to focus on technical delivery and platform ownership.

Key Responsibilities
1. Mobile Application Development
Take ownership of iOS and Android applications.
Maintain, troubleshoot and develop new features using Flutter and Dart.
Manage application builds, testing and releases to the Apple App Store and Google Play Store.
Manage release pipelines using Fastlane, TestFlight, Google Play Console and Firebase App Distribution.
Troubleshoot mobile-specific issues, including push notifications, permissions, device compatibility and application performance.
Work with native Swift and Kotlin code where required.
2. Backend Development & API Integrations
Maintain and develop backend services using PHP 8.4 and Symfony.
Manage REST API integrations, authentication and authorisation.
Maintain PostgreSQL databases and Doctrine ORM.
Develop and maintain background workers, scheduled tasks and automated data synchronisation.

2. Backend Development & API Integrations
Maintain and develop backend services using PHP 8.4 and Symfony.
Manage REST API integrations, authentication and authorisation.
Maintain PostgreSQL databases and Doctrine ORM.
Develop and maintain background workers, scheduled tasks and automated data synchronisation.
Manage Firebase Cloud Functions using Node.js/TypeScript.
Maintain integrations with third-party CRM platforms, including APIs and webhooks.
Ensure accurate and reliable synchronisation of membership, booking, class, contract and payment data.
3. Cloud Infrastructure & DevOps
Maintain and manage AWS infrastructure, including EC2, Aurora, S3, EFS, ECR and Secrets Manager.
Manage load balancing, autoscaling and application hosting environments.
Maintain Docker-based environments and nginx configuration.
Manage CI/CD pipelines using GitHub Actions.
Ensure infrastructure is secure, reliable, scalable and appropriately maintained.
Manage environment configuration, access permissions, credentials and secrets.
4. Firebase & Application Services
Maintain Firebase services, including Authentication, Firestore, Cloud Functions, Remote Config and Cloud Messaging.
Monitor application stability through Crashlytics and Firebase Analytics.
Maintain push notification functionality and related integrations.
Troubleshoot issues across Firebase services and connected applications.

5. Monitoring, Security & Maintenance
Monitor application and infrastructure performance using Grafana, Loki and Crashlytics.
Investigate and resolve production issues.
Maintain appropriate backup, recovery and disaster recovery procedures.
Implement security best practices across applications, infrastructure, databases and administrative tools.
Proactively identify technical risks, performance bottlenecks and opportunities for improvement.
Maintain technical documentation and ensure systems are maintainable over the long term.

6. Third-Party Integrations & Content Platforms
Maintain integrations with third-party CRM platforms, which act as the primary data source for application functionality.
Support integrations with Firebase, InBody, Google Translate, Pexels and external website content feeds.
Maintain WordPress-connected content feeds and integrations where required.
Ensure third-party services communicate reliably with mobile applications and backend systems.

Technical Environment
The developer will be responsible for maintaining two distinct technical environments.

Mobile Development
Flutter / Dart (iOS and Android)
Native Swift and Kotlin
Bloc / Cubit
Dio
Hive

Backend Development
PHP 8.4
Symfony 6.4
REST APIs and OAuth
PostgreSQL 17
AWS Aurora
Doctrine ORM
Symfony EasyAdmin
Node.js / TypeScript

Cloud Infrastructure & DevOps
AWS EC2, Load Balancing and Autoscaling
AWS Aurora, S3, EFS, ECR and Secrets Manager
Docker and nginx
GitHub Actions
Fastlane

Firebase & Application Services
Cloud Functions
Firebase Authentication
Firestore
Remote Config
Firebase Cloud Messaging
Crashlytics and Analytics

Monitoring & Integrations
Grafana
Loki
Slack alerts
Third-party CRM APIs and webhooks
WordPress integrations
External content and data feeds

Essential Requirements
We are looking for someone with strong hands-on experience across the following areas:

CRM Integration Experience: Previous experience integrating with PerfectGym CRM is a key requirement, given its role as the primary data source for both platforms. Experience with its APIs, webhooks and data synchronisation is particularly important.
Flutter & Dart: Strong commercial experience developing and maintaining cross-platform iOS and Android applications.
Mobile App Releases: Proven experience managing application builds, signing, testing and publishing releases through App Store Connect and Google Play Console, including Fastlane and TestFlight.
PHP & Symfony: Strong backend development experience, ideally with Symfony 6 or later.
PostgreSQL & Doctrine: Experience managing relational databases, queries, ORM and database performance.
Firebase: Experience with Cloud Functions (Node.js/TypeScript), Authentication, Firestore, Cloud Messaging, Remote Config and Crashlytics.
AWS & DevOps: Practical experience managing AWS infrastructure, including EC2, Aurora, S3, ECR, Secrets Manager, load balancing and autoscaling.
CI/CD: Experience building and maintaining automated deployment pipelines using GitHub Actions.
API Integrations: Strong experience working with REST APIs, OAuth, webhooks and scheduled data synchronisation.
Security: Understanding of infrastructure security, access management, secrets handling, backups and recovery.

Desirable Experience
Native iOS development using Swift.
Native Android development using Kotlin.
Experience troubleshooting mobile permissions, push notifications and native build configurations.
Monitoring and logging experience using Grafana, Loki and Firebase Crashlytics.
WordPress development and third-party content integrations.
Experience independently maintaining and supporting live production applications.


What Makes This Role Different?
This is not a role focused solely on mobile application development or backend engineering. You will have responsibility for the complete technical ecosystem behind two live mobile platforms.
You will become the primary technical owner of both applications, with the opportunity to influence their ongoing development, architecture, performance and reliability.
You will work closely with our internal delivery team, while client communication, project coordination and account management remain within our organisation.