Decision Framework · UK 2026
Build vs Buy: Should You Build AI Agents In-House?
A clear decision framework for whether to build AI agents in-house, buy off-the-shelf, or use an agency. Includes real UK 2026 costs for each path.
In-house cost
£200k+/yr
SaaS cost
£15k+/yr
Agency cost
£8k–£25k build
Best for SMEs
Agency
The playbook
- 1
Build in-house — when it makes sense
If you have 50+ planned agents, deep AI engineering talent already, and core IP to protect. Realistic cost: £200k+/yr (2 engineers + infra).
- 2
Buy SaaS — when it makes sense
For generic, well-defined use cases (helpdesk, CRM enrichment) where customisation isn't critical. Cost £15k+/yr per seat at scale.
- 3
Use an agency — when it makes sense
For UK SMEs with 1–10 planned agents, who need custom logic but don't want to build a team. Cost £8k–£25k build + £6k–£15k/yr run.
Common pitfalls
- Building in-house with no AI engineering experience (3× cost, 6× time)
- Buying SaaS expecting it to fit perfectly (it never does)
- Hiring a freelancer for production AI (single point of failure)
What you walk away with
Right path for your situation
Realistic budget envelope
Avoided £100k+ wrong-path mistake
Frequently asked
What's the agency advantage long-term?+
Speed to ROI and capped downside. You can always bring in-house later once you've proven the model.