Zapier vs Google Apps Script: Understanding the Tradeoffs
Zapier and Google Apps Script both automate work. That is where the similarity ends.
If you are deciding between them, or dealing with an automation that no longer behaves, the right question is not “Which tool is better?”
The right question is “What tradeoffs am I making?”
This post explains:
- What Zapier is good at
- What Apps Script is good at
- Where each approach breaks down
- Why many businesses start with Zapier and later need Apps Script
- How to choose safely based on risk, not convenience
No hype. No tool shaming. Just clarity.
Zapier is designed to connect systems quickly.
It excels at:
- Prototyping workflows
- Simple trigger to action automations
- Non-technical setup
- Cross-platform integrations
Example: “When a form is submitted, add a row to a spreadsheet and send an email.”
That is Zapier at its best. It lowers the barrier to automation, which is genuinely valuable.
Google Apps Script is designed to extend Google Workspace itself.
It excels at:
- Deep control of Gmail, Sheets, Docs, Drive, and Calendar
- Custom logic and branching
- State management
- Long-running or repeat-safe systems
- Internal tools that behave predictably over time
Apps Script is not a connector. It is an execution environment.
That distinction matters.
The Core Tradeoff: Speed vs Control
Zapier optimises for speed of setup.
Apps Script optimises for control and correctness.
That tradeoff shows up in predictable ways.
Zapier usually fails quietly, not dramatically. Common pressure points include:
1. Hidden State Zapier workflows often lack explicit memory. This makes it difficult to prevent duplicates or safely retry failed steps.
2. Cost Scaling With Volume Zapier charges per task. As workflows grow, cost increases.
3. Limited Debugging When something goes wrong, visibility is shallow. Fixes become guesswork.
4. Complex Logic Becomes Fragile Complex conditions quickly become hard to reason about.
At a certain point, the automation still works, but nobody full understands it. That is a risk.
Apps Script has tradeoffs too.
1. Higher Skill Requirement Someone has to design and write the logic (JavaScript). It is not plug and play.
2. Slower Initial Setup Building something properly takes longer than connecting steps visually.
3. Responsibility for Design Decisions If an Apps Script automation fails, it is because of how it was designed, not because a platform abstracted the risk away.
The Automation Lifecycle Pattern I See Repeatedly
This pattern shows up again and again.
- A business uses Zapier to move fast
- The automation works and becomes relied upon
- Volume increases
- Edge cases appear
- Duplicates, loops, or silent failures start
- Nobody is sure what is safe to change
At that point, the question is no longer “How do we automate this?”
It is “How do we make this safe?”
That is where Apps Script usually enters the picture.
Why Apps Script Is Often the Fix, Not the First Choice
Apps Script is rarely chosen first because:
- It looks technical
- It requires design thinking
- It does not advertise convenience
But it is often chosen later because:
- It can enforce state
- It can be made idempotent
- It behaves the same way every time it runs
It is the difference between an automation that works and a system that can be trusted.
Which One Should You Use?
A simple rule of thumb:
Use Zapier when:
- The workflow is simple
- Duplication would not be catastrophic
- Speed matters more than precision
- You are still experimenting
Use Apps Script when:
- The workflow runs daily or continuously
- Emails, money, or client data are involved
- Duplicate actions would cause harm
- You need the automation to be boring and reliable
Neither tool is wrong.
Using the wrong tool for the wrong job is where problems start.
If You Are Already Dealing With a Problem
If you are reading this because:
- Zapier is sending duplicate emails
- A workflow keeps repeating
- You are afraid to touch an automation that “mostly works”
That is common.
It usually means the system has outgrown the tool it started in.
That is fixable.
How I Can Help
I design and rebuild Google Workspace automations with safety in mind.
That includes:
- Replacing fragile Zapier workflows with Apps Script
- Adding state and safeguards to existing systems
- Diagnosing loops and duplication issues
- Designing automations that survive growth
Details are here:
https://empowerautomation.co.uk/services
And real-world breakdowns live here:
https://empowerautomation.co.uk/system-logs
Automation is not just about making things happen.
It is about making sure they only happen once.
This post documents a real automation failure mode. Similar failures often appear under labels such as automation loops, duplicate triggers, silent retries, and state loss.