Build vs Buy: When Custom Automation Beats Off-the-Shelf SaaS

The Default: Buy First

Most businesses start with off-the-shelf software. It makes sense; someone else has already built the tool, tested it, documented it, and supports it. You sign up, pay monthly, and you’re running.

For many use cases, this is exactly right. You shouldn’t build a custom email client or a custom spreadsheet application. Gmail and Google Sheets exist. Use them.

But there’s a category of software that businesses buy when they should build: the automation and integration layer. The tools that connect your existing systems, process your data, and handle your specific workflows.

This is where the build-vs-buy decision gets interesting.

When Buying Makes Sense

The problem is generic. Sending marketing emails, managing a CRM, tracking projects, hosting a website; these are solved problems. Hundreds of excellent tools exist. Building your own would be reinventing the wheel.

The tool fits without modification. You sign up, configure a few settings, and it does what you need. No workarounds, no missing features, no frustration.

The cost is proportional to the value. £50/month for a tool that saves 10 hours/month is a great deal. The ROI is clear and the cost is predictable.

You need it today. Off-the-shelf tools are immediate. Custom development takes days to weeks. If you need a solution by Friday, buy one.

Someone else maintains it. Updates, security patches, feature improvements; the vendor handles all of it. Your team focuses on using the tool, not running it.

When Building Makes Sense

The problem is specific to your business. Your workflow has steps, conditions, and exceptions that no generic tool handles well. You’re spending more time configuring workarounds than you’d spend building the real thing.

You’re chaining multiple tools together. When your solution requires Tool A → Zapier → Tool B → Make → Tool C, the integration layer is the product. And you’re paying for three subscriptions plus two integration platforms to do what one custom script could do directly.

The ongoing cost exceeds the build cost. If you’re paying £150/month for SaaS tools that a £1,500 custom build could replace, the build pays for itself in 10 months, and then saves you £1,800 per year, every year after.

Your data lives in Google Workspace. If the SaaS tools are primarily reading from and writing to Google Sheets, Gmail, Drive, and Calendar, you’re paying a middleman to access your own data. Apps Script accesses it natively, for free.

Reliability matters more than speed-to-launch. Off-the-shelf tools have their own bugs, outages, and limitations. Custom-built automation gives you full control over error handling, monitoring, and recovery. When the automation is business-critical, owning it matters.

You need it to evolve with your business. SaaS tools evolve on the vendor’s roadmap, not yours. Need a feature? Submit a request and hope it makes the cut. Custom automation evolves when you need it to; a call to your developer, a few hours of work, and it’s updated.

The Decision Framework

Ask these five questions:

1. Is this a core process or a commodity?

Commodity: Email hosting, file storage, video conferencing. Buy these. Always.

Core process: The specific way your business handles leads, processes orders, generates reports, manages clients. These are candidates for building.

2. How much am I paying in SaaS fees for this workflow?

Add up every subscription involved in the workflow, not just the main tool, but the connectors, the integrations, the add-ons. Compare the annual total against the one-time cost of building a custom solution.

If the annual SaaS cost exceeds the build cost, the decision is straightforward.

3. How much time do I spend on workarounds?

If you’re spending hours each month on manual steps that the SaaS doesn’t handle; exporting data, reformatting, re-uploading, fixing errors the tool creates; that time has a cost. Add it to the SaaS fees.

4. Does the tool match my process, or have I changed my process to match the tool?

If you’ve restructured how your team works to fit a SaaS tool’s limitations, you’ve paid a hidden cost in efficiency and flexibility. Custom automation matches your process; you don’t match the tool.

5. What happens if the vendor disappears or changes pricing?

SaaS vendors get acquired, pivot, raise prices, or shut down features. If your business depends on a tool, that dependency is a risk. Custom code that you own has no vendor risk.

Real Example: The Three-Tool Stack

A client was using:

Tool A (£45/month): Captured web form submissions and enriched them with basic data
Zapier (£30/month): Connected Tool A to Google Sheets and triggered email sequences
Tool B (£60/month): Managed the email sequences with timing, personalisation, and tracking

Total: £135/month = £1,620/year

The entire workflow lived inside Google’s ecosystem. Forms → Sheets → Gmail. The three tools were middlemen adding cost, complexity, and failure points between Google services that already talk to each other natively.

The custom build: One Apps Script project that captures form submissions, processes and enriches the data in Sheets, manages an email sequence with timing and personalisation through Gmail, and tracks opens and responses in the spreadsheet.

Build cost: £900 (one-time) Ongoing cost: £0 Break-even: 7 months Annual savings after year 1: £1,620/year

The custom build also:

Processes instantly (the SaaS chain had 5-15 minute delays)
Has full error handling (the SaaS chain failed silently at connection points)
Is fully customisable (the client has since added 3 new features at minimal cost)
Has no vendor dependency (no risk of price changes or service discontinuation)

The Hybrid Approach

Build vs buy isn’t always either/or. The smartest approach is often hybrid:

Buy the platforms. Google Workspace, your CRM, your project management tool; use best-in-class SaaS for the core platforms.

Build the connections. The automation, integration, and custom workflow layer; build this in Apps Script (or similar). This is where generic tools struggle and custom development shines.

Replace the middlemen. Any SaaS tool whose primary job is moving data between platforms you already own? That’s a build candidate.

Making the Decision

If you’re unsure whether to build or buy, the answer is usually: audit first, decide second.

Map out your current tools, what they cost, what they do, and where the pain points are. The picture that emerges usually makes the decision obvious.

Want Help Deciding?

At Empower Automation, we start with an honest audit. Sometimes the answer is “keep the SaaS, it’s the right tool.” Sometimes it’s “this is costing you thousands per year for something Apps Script can do for free.” We’ll tell you which is which.

Book a free 15-minute automation audit →

Bring your SaaS stack. We’ll tell you what’s earning its keep and what’s ready to be replaced.

Nicola Berry is the founder of Empower Automation, based in Falkirk, Scotland. Helping businesses invest in the right tools; whether built or bought.