saas strategy

Build vs Buy Software: A Decision Framework

Choose between buying SaaS, configuring a platform and custom development by comparing the required workflow, differentiation, available capacity and lifecycle cost. Begin with the possibility of improving the existing process. There is no universal winner: the right approach is the smallest one that meets the essentials and can be maintained by a named team.

Decide what must be different

Describe the outcome without naming a technology. An agency may need consistent approval of client work. A SaaS product could provide the workflow; a configured platform could assemble it; custom software could implement unusual rules. A shared checklist might be enough if the main problem is unclear responsibility.

Ask whether the unusual part creates meaningful value or simply reflects a habit. A workflow that is different from a vendor’s default does not automatically justify custom development. Conversely, forcing a genuinely distinctive operation into a rigid product may create expensive workarounds. Record the evidence for the difference before making it an architectural commitment.

List non-negotiable constraints for data, access, accessibility, integrations and exit. Give each a responsible reviewer. Any approach that cannot plausibly satisfy those constraints needs further investigation or removal from consideration, regardless of its apparent speed.

Compare the approaches

A decision matrix without an arbitrary winner
DimensionBuy SaaSConfigure or use no-codeCustom development
Workflow fitStrong when standard behaviour matches the jobAdaptable within platform rulesCan target unusual needs, subject to scope and delivery quality
Time to usable resultSetup may be quick; adoption and migration still take workConfiguration and validation can be substantialDiscovery, implementation and ongoing releases need capacity
DifferentiationUsually limited by vendor roadmapPossible within supported logic and data modelPotentially high, if the difference is valuable
MaintenanceVendor runs product; team owns configuration and useTeam owns rules, dependencies and platform changesTeam owns application maintenance, operations and security work
IntegrationConfirm exact plan and supported data movementCheck connectors, limits and failure handlingInterfaces can be built but still need stable external APIs
AccessAvailable roles must fit requirementsPermissions may constrain the architectureControls require design, implementation and verification
PortabilityTest exports and contract termsAssess data and application-logic exit separatelyOwnership of source does not guarantee portable infrastructure
CostSubscription plus implementation and internal timePlatform fees plus configuration and maintenanceDevelopment plus hosting, support and ongoing change

The matrix describes trade-offs, not current product promises. Verify a named platform’s actual plan and terms before relying on them. No-code does not mean no technical responsibility: someone must understand the data model, manage changes and respond when a workflow fails.

An illustrative approval-workflow decision

Consider an eight-person agency that collects client feedback and confirms acceptance. The team assumes it needs a bespoke portal because email threads are difficult to follow. Its confirmed requirement is narrower: preserve the approved version, identify the approver and prevent one client seeing another’s files.

First trial an agreed approval record in the existing workspace. If that meets the need, stop there. If the access model is inadequate, evaluate SaaS with the required client boundaries. A configured platform becomes relevant if the approval rules are unusual but expressible within its permissions and data model.

Custom development might become reasonable if complex approval rules are central to the business and no viable configuration meets them. Before choosing it, name who will own releases, backups, access recovery, dependency updates and support after the original developer finishes. A development quote that omits those responsibilities is incomplete.

The example does not prove which approach is cheapest. It shows a sequence that avoids committing to a large solution before establishing the actual constraint. The evidence that would change the decision should be written down: a failed access test, an essential integration gap or a confirmed differentiating rule.

Price the responsibility, not only the build

Compare costs over the same useful horizon. Include setup, migration, training, ongoing administration, support, overlap and exit. Separate supplier cash costs from the value of internal time. For custom development, include the expected effort to change and operate the software after launch, with uncertainty ranges rather than a false fixed forecast.

Ask what happens if the person maintaining the system leaves. Can another colleague understand it from documentation and a handover? Are the accounts owned by the organisation? Can the team restore an export or backup? These questions apply to configured and purchased software as well as custom applications.

Use the ownership-cost guide to build a comparable estimate. The SaaS calculator deliberately does not model a full custom-development budget; do not force a complex project estimate into a per-seat subscription formula.

Distinguish a website from an application

A marketing website and an application with accounts and business logic have different needs. StuartKerrs.com's Webflow and Bubble comparison explores that narrower platform choice. Related publication from the same publisher.

For your decision, identify whether the essential outcome is publishing information or operating a shared process with persistent records and permissions. A visually impressive page builder is not evidence that a platform supports the required application logic. Equally, a powerful application platform may add unnecessary maintenance for a straightforward publication.

Write the decision before committing

Problem and confirmed requirements:
Approaches considered, including current process:
Essential gates and supporting evidence:
Preferred approach and reasons:
Expected cost range and exclusions:
Who operates and maintains it:
Exit route and unresolved dependencies:
Smallest pilot that could change the decision:
Approval owner and review trigger:

Start a pilot around the riskiest assumption, not the easiest demonstration. If all approaches remain uncertain, return to the requirements worksheet and narrow the problem. Buying later after a useful investigation can be a better decision than selecting a platform to create a feeling of progress.