SaaS B2B platform vs custom-built: what's the difference?

Every SME manufacturer or wholesaler planning a B2B webshop eventually faces the same choice: use an existing SaaS platform, or have it custom-built by a software agency. Both routes solve the same need, but differ sharply in cost, speed, and who stays in control of what changes later.

This trade-off is known in software as "build vs buy". For a business with 20 to 300 employees, an existing ERP and a growing product catalog, that choice carries more weight than for a simple website: a B2B platform touches pricing, customer relationships and daily order processing.

What custom-built actually involves

With a custom build, an agency or development team builds a platform from a blank canvas, or starts from an open-source base such as Shopware or Magento. Every feature, from customer-specific pricing to an ERP integration, comes through a separate development track. You get exactly what you ask for, provided the request is described clearly enough and the budget holds up.

That track usually runs on day rates: analysis, design, development, testing, delivery. Every change after launch, a new pricing rule, an extra ERP field, a modified checkout flow, goes through that same track again.

What a SaaS platform actually involves

With a SaaS platform such as Fonda, you use functionality that already exists and is built and maintained for multiple customers at once. Customer-specific pricing, a self-service portal, PIM, DAM and standard ERP connectors to SAP, Business Central, AFAS or Exact come ready-made. You configure the platform to your situation instead of having each part programmed.

Updates, security patches and new features land automatically for all customers at the same time, usually without a separate project for each one.

The five differences that matter most

Timeline. A custom build for a wholesaler typically runs 6 to 18 months, from first conversation to go-live. A SaaS platform with standard connectors goes live within a month on average, with the timing of the ERP integration partly depending on whoever manages that ERP.

Cost structure. Custom development requires a large upfront investment, followed by an ongoing budget for maintenance and changes, often billed by the day. A SaaS platform runs on a fixed or predictable monthly price; with Fonda, that price stays the same regardless of the number of users or SKUs.

Maintenance and risk. With custom development, the business itself carries responsibility for updates, security and keeping integrations current. If the developer leaves the agency, the knowledge of the code often leaves with them. With SaaS, that responsibility sits with the vendor, who maintains the functionality for all customers at once.

Flexibility. Custom development can build literally any requested feature, unconstrained by an existing product model. A SaaS platform doesn't offer that freedom in full: functionality that doesn't fit the platform stays harder to build, or needs an external integration.

Dependency. With custom development, continuity depends on one agency or a small development team. With SaaS, continuity depends on the vendor as a company, with a product roadmap that moves forward for all customers together.

When custom-built remains the better choice

For a business with processes that no existing platform supports, with enough budget and internal IT capacity to carry its own development long-term, custom-built stays a defensible choice. That also holds when the platform itself needs to form a competitive advantage, not just a supporting tool for sales.

When a SaaS platform pays off more

For most SME manufacturers and wholesalers with 20 to 300 employees, a SaaS platform covers the core needs: customer-specific pricing, ERP integration, PIM, DAM and a self-service portal. The question then shifts from "can this be built" to "does a platform for this already exist, and does it cover my situation". For standard e-commerce and customer management processes, the answer is usually yes, at a fraction of the cost and timeline of a custom build.

Frequently asked questions

Is custom development always more expensive than a SaaS platform?

At the outset, the bill for custom development is almost always higher, and an ongoing maintenance budget comes on top of that. A SaaS platform with a fixed monthly price makes the total cost over several years more predictable.

Can a SaaS platform integrate with my ERP as well as a custom solution?

For the most widely used ERP systems, such as SAP, Business Central, AFAS and Exact, SaaS platforms like Fonda offer standard connectors that sync in real time. For a less common or heavily customized ERP, a custom integration may still be needed.

How long does a custom build take compared to a SaaS implementation?

A custom build typically takes 6 to 18 months. A SaaS platform with standard onboarding goes live within a month on average.

What happens to my platform if the development agency shuts down?

With custom development, the code remains company property, but the knowledge to keep maintaining it often leaves along with the agency or the developers who knew the project. With a SaaS platform, maintenance stays with the vendor, regardless of who set up the original project.

Is a SaaS platform as flexible as custom development?

Not entirely. A SaaS platform covers a broad set of standard functionality, but a process that deviates strongly and falls outside that set still needs an external integration or a change not every platform allows.