Short answer: Use an API when the system has a good one. Use a workflow tool (n8n) to connect modern apps quickly and cheaply. Use RPA when the system can only be operated through its screen (legacy, government portals, desktop).
The Three Approaches
- API integration: systems talk to each other directly. The most stable option.
- Workflow automation (n8n, Make, Zapier): connects many apps with visual connectors. Fast to build.
- RPA: a bot imitates a person's clicks and typing in the UI. Flexible for systems without an API.
Comparison
| Criterion | Custom API | Workflow (n8n) | RPA |
|---|---|---|---|
| Build speed | Slow-medium | Fast | Medium |
| Long-term stability | High | High | Medium (fragile if UI changes) |
| Requires API access | Yes | Usually | No |
| Fits legacy/desktop | No | No | Yes |
| License cost | Low | Low | Varies |
| Maintenance | Low | Low | Medium |
Decision Tree
- Does the system have an API or webhook? Yes → API or n8n. No → continue.
- Is there a scheduled file export (CSV, SFTP)? Yes → n8n plus file parsing. No → continue.
- Only available through the UI (web portal, desktop)? → RPA.
- Unstructured documents (PDFs, scans)? → add OCR/AI (see how).
Examples
- Syncing Shopify orders to an ERP with a REST API → n8n.
- Entering data into a government portal without an API → RPA.
- Payments between two internal systems you build → API.
- Hybrid: n8n triggers an RPA bot by webhook and reports the result back to Slack or WhatsApp.
Common Mistakes
- Using RPA when an API exists → higher maintenance cost.
- Forcing n8n onto a system that only has a UI.
- Skipping error handling and monitoring.
FAQ
Is RPA cheaper than an API?
Often at the start, because nothing in the system changes, but maintenance can cost more if the UI changes often.
Can n8n replace RPA?
For systems with an API, yes. For apps without one, you still need RPA or browser automation.
Which pays back fastest?
Usually workflow automation, then RPA, then custom APIs.
Next steps
Unsure? Describe your workflow and the Oneflux team will recommend the most economical approach.