Technology

Delphi

Programming language and IDE for Windows applications (Embarcadero). Many companies still run Delphi legacy systems that need modernisation.

Delphi was one of the most popular tools for Windows development in the 1990s and 2000s. Many companies still run critical Delphi applications – for ERP, warehouse, production control or vertical software. These systems often run reliably, but maintenance, extension and lack of Delphi developers are becoming a problem.

What is Delphi?

Delphi is an integrated development environment (IDE) and language (Object Pascal) for building Windows applications. Originally released by Borland in 1995, it is now developed by Embarcadero (RAD Studio). Delphi was notable for its visual RAD approach: developers could build UIs with drag-and-drop and the VCL (Visual Component Library) to create Windows apps quickly. Modern versions support cross-platform (Windows, macOS, Linux, iOS, Android) via FireMonkey (FMX).

How does Delphi work?

Delphi compiles Object Pascal to native machine code – applications are fast and need no runtime. The VCL provides UI components (buttons, grids, dialogs) that are placed by drag-and-drop. Database access uses ADO, dbExpress or FireDAC. The IDE includes debugger, profiler and unit testing. Legacy Delphi apps often use BDE (Borland Database Engine) or direct Firebird/Interbase connections.

Practical Examples

ERP: A mid-size manufacturer has run a Delphi-based ERP for 15 years with 200+ tables and complex business logic.

Lab software: A diagnostics lab uses a Delphi app for analyser control, sample management and reporting.

Vertical software: An insurance broker uses a Delphi desktop app for contract management, commissions and client care.

Production control: A Delphi app controls CNC machines via serial interfaces and shows production data in real time.

Typical Use Cases

Legacy maintenance: Keeping existing Delphi systems stable and adding features

Modernisation: Gradual migration from Delphi to web or cross-platform

Replacement: Full rewrite as a web app while reusing business logic

API integration: Exposing Delphi apps via REST to CRM, e-commerce, etc.

Data migration: Moving data from Delphi-specific DBs to modern DBMS

Advantages and Disadvantages

Advantages

Proven: Delphi apps often run stably for decades
Performance: Compiled code is fast and lightweight
RAD: Quick prototypes and changes
Business logic: Years of use have produced valuable, tuned logic

Disadvantages

Skills: Fewer developers know Delphi/Object Pascal
Licence cost: RAD Studio Enterprise is thousands per developer per year
Outdated architecture: Desktop-only does not fit cloud and mobile-first
Vendor lock-in: Embarcadero is the only vendor
Maintenance: Older Delphi versions are no longer supported

Frequently Asked Questions about Delphi

Should I modernise or replace my Delphi system?

Modernise (refactor, add APIs) when the business logic is complex and proven and the system is stable with limited change. Replace when the architecture is at its limit, you need web/mobile, or no Delphi developers are available. A hybrid – modern frontend, gradual backend replacement – is often the most pragmatic.

What does a Delphi migration cost?

Migrating a mid-size Delphi app (50–100 forms, 100–300 tables) to a modern web app is typically €100,000–300,000 and 6–18 months. Smaller apps from around €30,000. Drivers: complexity of logic, number of integrations, data migration and parallel operation during cutover.

What are alternatives to Delphi?

Desktop: C# with .NET WPF/WinUI (similar RAD, modern ecosystem). Cross-platform: Flutter (desktop + mobile + web). Web: React/Next.js (frontend) + Node.js, Python or .NET (backend). Vertical software: Odoo (open-source ERP). Best alternative depends on target platform and requirements.

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