APIs and tools both execute logic in integrator.io, but they serve different purposes. Use this guide to decide which to build.
It is recommended to build reusable logic as a tool and if external access is required, create an API that invokes the Tool.
|
Use Case |
Use Tool |
Use API Builder |
|
Reusable internal logic |
✓ |
|
|
Logic used in Flows or AI Agents |
✓ |
|
|
Expose endpoint to external systems |
✓ |
|
|
Need custom HTTP configuration (URL, headers, methods) |
✓ |
|
|
Need custom error responses |
✓ |
|
|
Require retries and queueing |
✓ (in Flows) |
|
|
Long-running process |
✓ (in Flows) |
|
|
Strict 2-minute timeout acceptable |
✓ |
-
Logic is reusable across Flows, APIs, or AI Agents
-
The process runs internally within Celigo
-
You need Flow-level retries, queueing, or pause-on-error
-
The process may run longer than 2 minutes
-
You want to avoid unnecessary API call costs
-
Have one input and one output (JSON contract-based)
-
Do not support HTTP configuration
-
Do not customise error responses
-
Are context-aware (behaviour depends on where they run)
-
Require connection overrides at runtime
Tools require connection overrides at runtime.
-
The Tool defines required connection types.
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The calling Flow, API, agent, or nested tool must provide its own connections.
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If overrides are not supplied, execution fails.
Important
Connection overrides are mandatory, even when a tool is nested inside another tool.
This design ensures:
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Secure credential handling
-
No shared connection leakage
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Reusability across environments and accounts
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The process must be exposed externally
-
You need a REST endpoint with URL, method, and headers
-
You must customise success or error responses
-
A strict 2-minute synchronous execution is acceptable