# Should we build a custom AI tool or buy SaaS?

Buy SaaS when your process matches how the tool works. Build when the work is yours alone: your approvals, your exceptions, your mix of systems. Then watch the gaps. If people copy data between tools every week, those hours are the budget. A custom tool earns its cost when it removes them.

By Surinder Thakur, AI Product Designer. Published 31 Oct 2026. Updated 1 Nov 2026. Topic: [Building an AI tool](https://www.surinder.design/work?type=building-an-ai-tool).

## When is SaaS the right call?

When the job is common and your way of doing it is not special. Payroll, email and a help desk are solved problems.

The vendor spreads the cost across many customers, so you pay a fraction of a build. Bend your process to the tool and keep your money.

## When does a custom build win?

When the work is how your company is different. Your approval chain, your pricing exceptions, the 4 systems an invoice passes through.

SaaS makes you work around those. People fill the gaps with spreadsheets, copy and paste, and reminders. A custom tool or agent is built around them, so the gaps close.

## What are other teams doing?

Retool's 2026 build vs buy report surveyed 817 builders, including Retool customers. 35% had already replaced at least 1 SaaS tool with a custom build. 78% expect to build more of their own tools in 2026.

Read it with its bias: Retool sells a way to build internal tools. It still shows the direction.

## How do you decide without guessing?

Count the hours first. List the steps people do by hand around the tool, and who does them each week. Price those hours, then price the build.

The 2 week Blueprint does this and ends with a fixed build price. The decision rests on numbers, not on a demo.

## In 1 picture

2 questions decide it: is the job common, and who fills the gaps today.

Buy SaaS when:
- The job is common, like payroll or email
- Your process can bend to the tool
- A monthly fee beats paying for a build

Build when:
- The work is how you are different
- People bridge gaps by hand every week
- Approvals and exceptions are yours alone

## Sources

- [Retool · The build vs buy shift, 2026 report](https://retool.com/blog/ai-build-vs-buy-report-2026)

## Next questions

- [What does a custom AI tool cost?](https://www.surinder.design/work/what-does-a-custom-ai-tool-cost): A custom AI tool or agent costs from $20,000 to build here.
- [Why do AI pilots stall before real use?](https://www.surinder.design/work/why-ai-pilots-stall): AI pilots stall because a demo only proves the tool can work.
- [What do you get from a 2 week Blueprint?](https://www.surinder.design/work/what-you-get-from-a-blueprint): In 2 weeks you get a business case, a working prototype and a fixed build price.

Page: https://www.surinder.design/work/build-or-buy-an-ai-tool