Product Engineering
Modernise what you have, without stopping the business.
We move legacy systems to modern architecture and cloud in stages — paying down technical debt and adding new capability, including AI, while the platform keeps running.
- ISO 9001 certified
- NDA on request
- You own the code
Trusted by 100+ clients in 25 countries
What we offer
Our application modernisation services.
Take the complete service, or just the parts you need. Every engagement is shaped around your goals, your users and your budget.
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Assessment
Code, architecture and infrastructure review with a staged plan.
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Incremental re-platforming
Replacing parts of the system behind stable interfaces.
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Cloud migration
Moving workloads to managed cloud services.
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Data migration
Planned, tested moves with reconciliation.
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New capability
APIs and AI features added as the platform is modernised.
Why clients trust us
Real products, real businesses, since 2018.
From startups launching their first app to ministries and global brands, businesses in 25 countries rely on Appsums to build, run and grow their software.
- 15+
- years in IT
- 8+
- years as Appsums
- 100+
- clients
- 25
- countries
How we work
How we deliver application modernisation.
Six clear stages from first call to a product that keeps improving. You always know what is happening, what comes next and what it costs.
- Weekly demosSee real progress, not status reports
- One accountable leadA single person who owns delivery
- Written milestonesScope and budget agreed up front
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Stage 1 of 6
Discover
- Understand goals, users and market
- Prioritise features for launch
- Agree budget and timeline
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Stage 2 of 6
Design
- User journeys and wireframes
- Visual design and prototype
- Test with real users
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Stage 3 of 6
Build
- Agile sprints with weekly demos
- Code reviews on every change
- Integrations and admin tools
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Stage 4 of 6
Test
- Manual and automated testing
- Real-device and browser checks
- Performance and security checks
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Stage 5 of 6
Launch
- App store and cloud release
- Monitoring and crash reporting
- Launch-day support
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Stage 6 of 6
Support and grow
- Bug fixes and OS updates
- New features release by release
- Usage insights and advice
Client voice
What our clients say.
In their own words, from the founders and leaders we build for. All reviews
Technologies
The technology we build with.
Popular, proven tools that are easy to grow and easy to hire for, so your product is never locked in to us.
Most used for application modernisation:.NETJavaNode.jsAWSDockerPostgreSQLCI/CD
Web and mobile
- React
- Next.js
- Angular
- Vue.js
- TypeScript
- JavaScript
- Tailwind CSS
- Flutter
- Dart
- Swift
- Kotlin
- Jetpack Compose
- Android
- iOS
- Ionic
- Figma
Backend and data
- Node.js
- Express
- NestJS
- Python
- Django
- FastAPI
- PHP
- Laravel
- .NET
- Spring
- GraphQL
- Socket.IO
- MongoDB
- PostgreSQL
- MySQL
- MariaDB
- Redis
- Elasticsearch
- Firebase
- Supabase
- Prisma
Cloud and DevOps
- AWS
- Google Cloud
- DigitalOcean
- Docker
- Kubernetes
- Terraform
- GitHub Actions
- Jenkins
- Nginx
- Grafana
- RabbitMQ
- Kafka
- Jest
- Cypress
- Selenium
- Postman
- Jira
AI and integrations
- OpenAI
- Anthropic
- Gemini
- Llama (Meta)
- LangChain
- Hugging Face
- PyTorch
- TensorFlow
- Ollama
- NumPy
- Pandas
- scikit-learn
- Stripe
- PayPal
- Twilio
- WhatsApp Business
- Google Maps
- Shopify
- WordPress
Security and trust
Security, privacy and IP built into how we work.
Security by design
- Secure architecture and code reviews
- Encryption in transit and at rest
- Vulnerability checks before release
- Dependencies kept up to date
Data protection
- Least-privilege, role-based access
- Separate test and live environments
- Hosting in the region you choose
- Credentials handed back at the end
Contracts and IP
- NDA signed before detailed talks
- You own all code, designs and data
- Clear scope and statements of work
- Confidentiality for every team member
Quality and governance
- ISO 9001 certified quality management
- Documented, audited processes
- Progress and risk reports every sprint
- Release checklists and sign-off
ISO 9001 certified. Quality you can rely on.
Our quality management system is independently certified, so every project follows documented, audited processes from kick-off to support.
Explore more
Explore our full range of services.
Most clients start with one service and add others as they grow. The same team keeps the context.
FAQs
Frequently asked questions.
Anything else about application modernisation? Ask us directly. A real engineer reads every message.
Do we have to rewrite everything?
No. We modernise in stages so the business keeps running and value arrives early.
Can modernisation include AI?
Yes. AI features can be added as part of the plan.


















