Custom Apps,
with AI
Custom software, AI and websites for Singapore businesses. Thoughtfully designed. Built around you.
Let’s build somethingAbout Us
We’re APP404, an independent digital studio in Singapore. We turn “there must be a better way” into software that makes a difference.
We start by listening: to your ideas, your challenges, and the people who will use what we build. Then we bring design and development together to make the complex feel simple.
From a new website to a custom business platform, we care about the details that make everyday work better.
Find your next step*For eligible SMEs and qualifying activities, subject to approval. EDGE opens 30 September 2026. View eligibility ↗
Services
AI strategy & transformation
Find where AI can make a useful difference.
- AI consulting
- Readiness & data audits
- Use-case discovery
- Build-or-buy advice
- AI roadmaps
- AI-native workflow redesign
Explore all 6 capabilities
- AI consulting
- Readiness & data audits
- Use-case discovery
- Build-or-buy advice
- AI roadmaps
- AI-native workflow redesign
AI agents, chatbots & assistants
Make intelligence part of the everyday workflow.
- Custom AI applications
- AI agents & tool integrations
- Chatbots & copilots
- ChatGPT, Claude & Gemini integration
- RAG & knowledge search
- Document Q&A
- Content & report generation
- AI evaluation & cost controls
Explore all 8 capabilities
- Custom AI applications
- AI agents & tool integrations
- Chatbots & copilots
- ChatGPT, Claude & Gemini integration
- RAG & knowledge search
- Document Q&A
- Content & report generation
- AI evaluation & cost controls
Document AI & machine learning
Turn documents, images and data into useful information.
- Document processing & OCR
- Data extraction
- Text classification & NLP
- Computer vision
- Demand forecasting
- Predictive analytics
- Recommendation systems
- Model adaptation & fine-tuning
Explore all 8 capabilities
- Document processing & OCR
- Data extraction
- Text classification & NLP
- Computer vision
- Demand forecasting
- Predictive analytics
- Recommendation systems
- Model adaptation & fine-tuning
Websites & web applications
A clear first impression. A capable digital platform.
- Website design & development
- Website revamps
- Custom web apps
- Customer & staff portals
- Progressive web apps
- SEO, performance & UX audits
Explore all 6 capabilities
- Website design & development
- Website revamps
- Custom web apps
- Customer & staff portals
- Progressive web apps
- SEO, performance & UX audits
Mobile apps & digital commerce
Useful experiences wherever your customers are.
- iOS & Android apps
- Cross-platform development
- AI-enabled mobile apps
- E-commerce & m-commerce
- Booking & payment systems
- Subscriptions & memberships
Explore all 6 capabilities
- iOS & Android apps
- Cross-platform development
- AI-enabled mobile apps
- E-commerce & m-commerce
- Booking & payment systems
- Subscriptions & memberships
Custom software, ERP & enterprise
Build around your operation, with room to grow.
- Custom software development
- Enterprise applications
- Custom ERP & AI ERP
- CRM & sales systems
- Inventory & procurement
- HR & workforce management
- Finance & operational reporting
- Legacy system modernisation
Explore all 8 capabilities
- Custom software development
- Enterprise applications
- Custom ERP & AI ERP
- CRM & sales systems
- Inventory & procurement
- HR & workforce management
- Finance & operational reporting
- Legacy system modernisation
Automation & system integrations
Help your tools and teams work together.
- Workflow automation
- API & third-party integrations
- Power Apps & Power Automate
- Approvals & document workflows
- Data migration & synchronisation
- Reporting dashboards
Explore all 6 capabilities
- Workflow automation
- API & third-party integrations
- Power Apps & Power Automate
- Approvals & document workflows
- Data migration & synchronisation
- Reporting dashboards
Product design & startup MVPs
Explore the right product before building more of it.
- Product discovery
- UI/UX research & design
- Wireframes & design systems
- Working clickable demos
- MVP development
- AI-assisted development
- Usability & quality testing
Explore all 7 capabilities
- Product discovery
- UI/UX research & design
- Wireframes & design systems
- Working clickable demos
- MVP development
- AI-assisted development
- Usability & quality testing
Cloud, monitoring & ongoing support
A considered launch. A clear plan for what follows.
- Cloud deployment & migration
- Availability & error monitoring
- Performance & cost reviews
- Backup & recovery planning
- Security updates & maintenance
- SLA-based support
- New features & integrations
Explore all 7 capabilities
- Cloud deployment & migration
- Availability & error monitoring
- Performance & cost reviews
- Backup & recovery planning
- Security updates & maintenance
- SLA-based support
- New features & integrations
Portfolio
01 / 03Owner dashboard
OneFitfinity
A gym in Clementi, Singapore, offering personal training and strength coaching. OneFitfinity focuses on helping people move with confidence, with safety and individual guidance at the centre of each session.
Approach
Listen first. Define what matters.
Map your workflow, users and priorities together. Agree the scope, milestones and acceptance criteria before the build.
- Workflow & user discovery
- Clear scope & milestones
- Agreed success measures
Click it. Test it. Shape it.
Try a working clickable demo of the key journey. Use real scenarios to refine the experience before full development.
- Working, clickable screens
- Your feedback built in
- A focused first release
Make progress visible.
Review working releases in stages. Test permissions, integrations and edge cases, then complete user acceptance together.
- Staged releases & reviews
- Integration & permission checks
- User acceptance testing
Launch with a watchful eye.
Go live with a handover, recovery plan and monitoring for the agreed services. Follow availability, errors and performance after deployment.
- Deployment & handover
- Availability, errors & performance
- Backup & recovery arrangements
Clear support. Room to grow.
Agree a written SLA before launch, then keep improving with planned maintenance and separately scoped extensions.
- Named systems, hours & contacts
- Severity, response & escalation targets
- Separate restoration & resolution targets
- Agreed monitoring & recovery objectives
- Defined maintenance allowance
- New features: scope, estimate & approval
Contact Us
A new idea. A stubborn problem. A better way to work.
We’d love to hear about it.
