.NET Core vs WebForms: What SMEs Need to Know Before Upgrading

If your business still relies on an older ASP.NET WebForms application, you may be wondering whether it’s finally time to move to .NET Core. The short answer is yes — but understanding why helps you make the right decision, choose the right upgrade path and avoid overpaying on unnecessary rewrites.

This article explains the differences between WebForms and .NET Core in plain English and outlines what SMEs should consider before upgrading.

---

WebForms vs .NET Core: The Core Differences

WebForms was designed for a different era — the early 2000s — when websites were server-heavy, non-responsive and full of ViewState-driven forms. By contrast, .NET Core (now simply “.NET”) is fast, lightweight, cross-platform and built for modern, mobile-first applications.

1. Performance

• .NET Core: Extremely fast, no ViewState, minimal overhead, async-first.
• WebForms: Heavy page lifecycle, large HTML output, many round trips.

Real-world SME systems typically load 2–5× faster after upgrading from WebForms to .NET Core Razor Pages.

2. Security

• .NET Core includes modern middleware, hardened cookie handling and up-to-date cryptography.
• WebForms relies on deprecated authentication systems and outdated pipeline features.

For businesses handling customer data, staff data, photos or invoices, upgrading provides major security benefits.

3. Future Support

• .NET Core receives regular updates, LTS releases, performance improvements and security patches.
• WebForms is no longer developed — and hasn’t been for years.

Staying on WebForms increases operational risk because the ecosystem (libraries, NuGet packages, browsers) is moving on.

4. Hosting & Deployment

• .NET Core can run on Windows, Linux, Docker or cloud hosting.
• WebForms requires Windows + IIS and cannot run in containers.

Modern hosting opens the door to cheaper servers, auto-scaling and greater reliability.

---

Which SME Systems Benefit Most from Upgrading?

In my experience modernising SME systems, .NET Core delivers the biggest improvements for applications that:

• Rely heavily on dashboards, data entry forms or admin panels
• Have slow SQL or code-behind logic mixed with UI
• Are used on phones or tablets (WebForms struggles here)
• Need API access for mobile apps or partner integrations
• Have grown organically over 10+ years

If your staff complain about slowness, reliability or usability, upgrading is usually the most cost-effective solution.

---

Do You Need a Full Rewrite?

Not always — and often not at all. Many SMEs assume upgrading means rebuilding the entire application from scratch. That used to be true, but with .NET Core you now have multiple options:

Option A: Rebuild the whole app (only for extremely outdated systems)

This is appropriate when the existing system:

• Has no source control
• Has severe performance issues
• Contains large amounts of broken code
• Mixes UI + SQL + business logic in huge code-behind files

This is the most expensive route but gives complete freedom to redesign workflows.

Option B: Modernise one module at a time (recommended)

This is typically the smartest approach. You can:

• Keep your WebForms system running
• Create a new .NET Core project alongside it
• Migrate sections gradually: Quotes → Jobs → Invoices → Reports
• Share the same SQL database between old and new code
• Retire WebForms pages as their replacements launch

It’s lower risk, more affordable and keeps staff working without disruption.

Option C: Replace the backend with a .NET API

If your WebForms app contains lots of business rules, workflows or data transformations, you can extract these into a .NET Core API and keep the UI temporarily.

This gives you a clean, modern foundation for future front-end work.

---

Common WebForms Problems That Disappear After Upgrading

• ViewState bloat causing 300–600 KB pages
• SQL slowdowns due to old data-access patterns
• Postback overload making every click feel slow
• Hard-to-maintain code-behind files
• Outdated UI that doesn't work well on mobiles
• Frequent outages from brittle legacy code

.NET Core fixes all of these by design.

---

What Does a Modernised .NET Core System Look Like?

• Fast-loading Razor Pages with clean URLs
• Responsive layouts using Bootstrap 5 or Tailwind
• Async database access via Dapper or EF Core
• Secure authentication using ASP.NET Core Identity
• Structured logging and error tracking
• Optional APIs for mobile apps and integrations

The end result feels modern, smooth and ready for the next decade.

---

How Much Does It Cost to Upgrade?

Costs vary based on system size, but here are typical SME scenarios:

• Small app (5–10 key pages): £3,000 – £8,000
• Medium app (10–30 pages): £8,000 – £20,000
• Large/complex app (30+ modules): £20,000+

Most projects are incremental, meaning you modernise the system gradually without large upfront cost.

---

How New Media Aid Helps SMEs Upgrade

I specialise in helping SMEs modernise long-running systems safely and affordably. My approach always focuses on:

• Zero downtime
• Shared database migration (no data loss)
• Clean, maintainable .NET Core code
• Big UX improvements without rewriting everything
• Future-proofing with APIs, logging and security best practices

If your business relies on a WebForms system and you're unsure where to begin, I can provide a clear roadmap with costs, timelines and upgrade steps.

---

Thinking of Upgrading? Let’s Talk.

If you'd like an audit of your current WebForms application — or a second opinion on whether a full rewrite is necessary — just get in touch.

Email: ab@newma.co.uk
Phone: +44 7967 219288

Happy to help — no obligation.