Every growing UK small business hits the build-vs-buy question. CRM, booking system, e-commerce, member management, website, automation — each can be bought as SaaS or built bespoke. Picking wrong burns six-figure sums. Here's a framework for picking right.
When to buy
Off-the-shelf SaaS is the right answer when:
- Your workflow is genuinely standard (e-commerce, accounting, basic CRM, email)
- You don't have technical capacity to maintain custom systems
- The SaaS market is mature and competitive (lots of options, downward price pressure)
- You're early-stage and need speed over fit
- The lifetime cost over 5-7 years is materially less than custom
For most UK small businesses doing under £1m turnover, buying SaaS is the right answer for 80%+ of their tools.
When to build
Custom is right when:
- Your workflow is genuinely non-standard and no SaaS fits it well
- SaaS pricing scales painfully (per-user, per-customer, per-transaction)
- You need integration depth that off-the-shelf can't provide
- You're at a scale where ownership and control matter more than speed
- The bespoke solution gives you a competitive advantage that off-the-shelf can't
Examples we've seen work: two-sided ordering portals like Ash Workwear's, AI-augmented admissions CRMs, bespoke member management for clubs whose needs SaaS doesn't fit.
The maths
Buy-vs-build rule of thumb over a 5-year horizon:
- SaaS at £100-£500/month: ~£6,000-£30,000 over 5 years
- Custom build at £8,000-£15,000: one-off plus £200-£500/month running costs (£12,000-£30,000/year-of-ownership)
For most UK small businesses with standard workflows, SaaS wins on cost. For bespoke needs, custom wins on fit — and the cost difference narrows or flips at scale.
Hybrid patterns that work
The best technology stacks for growing UK businesses are usually hybrid:
- SaaS for the common stuff — accounting (Xero), email (Outlook/Google), CRM (HubSpot/Pipedrive), website (custom build on a clean stack)
- Custom for the unique stuff — your specific workflow, customer-facing experience, anything proprietary
Don't try to build everything. Don't try to SaaS everything.
Common mistakes
Building custom because "we want to own it"
For standard workflows, ownership has no upside. Use SaaS, save the money for what matters.
SaaSing the wrong thing
If your CRM, your portal, or your booking system is your core competitive differentiation, off-the-shelf might commoditise you.
Switching platforms every 18 months
Every migration costs you. Pick once, commit, iterate.
Where Bloomorbit fits
We build custom for the bits worth building custom — typically client portals, bespoke workflows, AI-augmented systems, two-sided platforms. We're honest about when off-the-shelf is the better answer.
A typical conversation with us starts with "we're thinking of building X" and ends with either "yes that's worth building, here's what it'd cost" or "actually you should use Y SaaS for that, save your money".
A note from the Bloomorbit studio
If you're weighing build vs buy, the free 10-minute call is the cheapest way to settle it. We'll give you a straight read and tell you when the right answer is "don't hire us, use a SaaS".