Case study · Public sector
The system everyone depends on, rebuilt safely
Many organisations rely on an Access database or VB6 application written years ago by someone who has left. This is how we rebuilt it as a secure web application, preserving the business rules hidden in the old code and moving users over in stages.
Project overview
Legacy desktop application rebuilt for the web.
- Industry
- Public sector
- Client
- Confidential
- Solution
- Legacy modernisation
- From
- Access, VB6, desktop apps
- Timeline
- 12–24 weeks
- Team
- 5 people
- Security
- SSO, roles, audit
- Data
- Migrated and cleaned
- Rollout
- Staged by team
Expected business outcomes
What the client set out to gain
Risk reduction is the headline benefit.
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Documented
Business rules
Rules hidden in old code written down and tested.
Every rule covered by a test case
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Secure
Access and audit
Single sign-on, roles and an audit trail.
Meeting organisational security standards
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Anywhere
Access for users
A browser instead of a shared drive and specific PCs.
Subject to access policies
Business challenges
Where the client started
Critical, fragile and understood by nobody.
Technology
Access database on a shared drive or VB6 on specific PCs.
Knowledge
The original developer has left.
Security
No proper user management or audit trail.
Reliability
Corruptions and locking problems with multiple users.
Risk
IT flags it as a risk every year.
Proposed solution
What the modernisation covers
The hard part is understanding the old system.
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Rule discovery
Old code, queries and forms analysed to extract business rules.
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Test cases
Every rule captured as a test the new system must pass.
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Web application
A modern, accessible web interface for existing workflows.
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Database migration
Data cleaned and migrated to a modern database.
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Security
Single sign-on, roles and audit logs.
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Integrations
Links to other systems rebuilt through APIs.
Project requirements
What the client asked us for
The request was to replace the old system. The key is not losing the rules it quietly enforces, so rule discovery and testing come first.
Users move over team by team, with the old system read-only for reference during transition.
What the project had to deliver
- 01Business rules preserved
- 02Secure web access
- 03Clean, migrated data
- 04Staged, low-risk transition
Key challenges & considerations
What made it harder, and what we did
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Undocumented logic in forms and macros
What we did
Business rules were documented from the forms and macros before rebuilding.
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Data quality issues
What we did
Data was cleaned during two rehearsal migrations.
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Users attached to the old screens
What we did
Familiar screens were kept where they worked, and users moved in stages.
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Reports nobody knew existed
What we did
Every report was inventoried, and the ones still in use were rebuilt.
What we watched for
- Document rules before rebuilding
- Test against old outputs
- Migrate data twice in rehearsal
- Move users in stages
Development process
Understand, rebuild, migrate
Rules are written down before code is written.
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Discovery
Old system analysed with its users.
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Rules and tests
Business rules documented as test cases.
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Rebuild
Web application built iteratively with users.
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Migration rehearsal
Data migrated and checked in test.
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Staged rollout
Teams move over one by one.
Technology stack
Modern, supportable technology
Chosen so the organisation can support it for years.
Front end
- React or Next.js
- TypeScript
- Accessible design system
Back end
- Node.js or .NET
- PostgreSQL or SQL Server
- REST / GraphQL APIs
Cloud
- Azure or AWS
- Managed databases
- CDN
Quality
- Automated tests
- CI/CD
- Monitoring and alerts
Quality assurance & deployment
Tested every sprint, released without drama
Testing ran alongside the build, not after it. Every feature was checked against its acceptance criteria in the sprint it was built in, and releases went through an automated pipeline.
- Automated unit and API tests, run on every change
- Code review by a second engineer before anything was merged
- Feature testing against written acceptance criteria
- Cross-browser and responsive checks on the agreed devices
- Security checks on access, sessions and data handling
Deployment
- 01Migration rehearsalData migrated and checked in test.
- 02Staged rolloutTeams move over one by one.
- 03Automated release pipelineThe same build moved from staging to production, with a tested rollback.
- 04Monitoring and warrantyError and uptime monitoring from day one, and six months of free bug fixing.
Final deliverables
A critical system that's no longer a risk
The organisation runs on a secure, documented web application that preserves the rules the old system enforced.
IT can support and extend it, and users work from any approved device.
- Preserved business rules
- Secure web app
- Migrated data
- Supportable technology
Handed over to the client
- 01Production applicationDeployed and monitored
- 02Source codeIn a repository the client can access
- 03Technical documentationArchitecture, setup and deployment
- 04Test suite and pipelineSo later changes stay safe
- 05Six-month warrantyFree bug fixing after delivery
Success metrics
How success is measured
| Measure | Outcome | How it is measured |
|---|---|---|
| Business rules | Documented | Every rule covered by a test case |
| Access and audit | Secure | Meeting organisational security standards |
| Access for users | Anywhere | Subject to access policies |
Verified reviews
What clients say about our web development work
Verified reviews from our clients on the same kind of work, published on Clutch.
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Web Development
Custom Web Development for a Software Solutions Company
We can rely on them to handle almost any task with confidence, as they consistently deliver good results.
Casper Hougaard Jensen
CEO & Co-Founder, Iterator IT Jul 2021 – Sep 2022
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Web Development
Web & Mobile App Development for a Software Development Company
They efficiently organized tasks and deliverables while promptly addressing questions.
Damien Retzinger
Founder, Graycore Jun 2021 – Feb 2023
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Web Development
Website Development for a Software Engineering Company
They have a broad understanding of different technologies.
Eugene Bosikov CEO, Ezibeline LLC Mar 2022 – Ongoing Verified review on Clutch (Eugene Bosikov, opens in a new tab)
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