guides
SaaS vs custom software: control, cost and margin
SaaS is excellent at commodity processes and poor at differentiating ones. The question is not which is better; it is which part of your operation is genuinely yours.
Outcomes
- Commodity processes belong in SaaS — payroll, accounting, email
- Differentiating processes are worth owning
- Subscription cost rises with success; build cost does not
- Data portability is the real lock-in question
- Integration quality often matters more than either choice
Problems this solves
Per-seat pricing punishes growth
Model the licence bill at your expected headcount in three years, not today's.
Roadmap dependency
With SaaS, features you need arrive when the vendor decides — or never.
Data lives elsewhere
Check export formats, API limits and residency before committing critical processes.
Realistic timeline
Week 1
Model three-year cost for both routes.
Week 2
Trial the leading SaaS option against your real process and data.
Weeks 3–4
Decide, and scope the first phase.
Build or buy
Buy something existing when
- Standard needs, small teams, and speed to value
Build custom when
- Specific workflows, heavy integration, or licence cost that scales badly
Many companies keep SaaS for commodity functions and build the operational core around it.
What moves the price
Seats and tiers
Feature gating often forces an upgrade for one required capability.
Integration and middleware
Connector subscriptions add a recurring line that is easy to overlook.
Customisation limits
Workarounds for missing features are paid in staff hours forever.
Where projects go wrong
Underestimating migration out
Ask for a real export before committing, not a documentation page.
Shadow spreadsheets
If teams still keep a sheet beside the tool, the tool does not fit.
FAQ
Questions buyers ask
Is custom always more expensive up front?+
Yes, almost always. The comparison only becomes interesting over three to five years.
Can we do both?+
Most of our clients do — packaged finance and a custom operational core.
Related pages
You already have the idea. Let's define what comes next.
Available in 12 languages
Avenryx Systems