Call API Block

Overview

The Call API block sends HTTP requests to external APIs and returns the response data. Use it to integrate with third-party services, fetch data from your own backend, or connect to any RESTful API.

Configuration

Request Method

Select the HTTP method for your API request.

Method	Description	Use When
GET	Retrieve data from the API	Fetching information, reading resources
POST	Send data to the API	Creating resources, submitting data, triggering actions

API Endpoint URL

Enter the complete URL of the API endpoint. Only HTTPS URLs are supported for security. Format: https://api.example.com/endpoint This field supports placeholders to build dynamic URLs:

https://api.example.com/users/{{step_1.output.user_id}}/profile

HTTP URLs are not allowed. All API requests must use HTTPS for secure communication.

Request Headers

Add HTTP headers required by the API. Common headers include authentication tokens, content types, and API keys. Adding headers:

Click “Add header”
Enter the header name (e.g., Authorization)
Enter the header value (e.g., Bearer {{api_token}})

Common headers:

Header	Example Value	Purpose
Authorization	`Bearer sk-xxxxx`	API authentication
X-API-Key	`your-api-key`	Alternative auth method
Accept	`application/json`	Request JSON response

Headers support placeholders for dynamic values:

Authorization: Bearer {{step_1.output.token}}

Query Parameters

Add URL query parameters that will be appended to the endpoint URL. Adding parameters:

Click “Add query parameter”
Enter the parameter name (e.g., page)
Enter the parameter value (e.g., {{current.page_number}})

Example:

Parameter	Value
limit	`10`
offset	`{{step_1.output.offset}}`
sort	`created_at`

This produces: https://api.example.com/items?limit=10&offset=0&sort=created_at

Request Body

For POST requests, provide the JSON payload to send. The body must be valid JSON format:

{
  "name": "{{step_1.output.name}}",
  "email": "{{step_1.output.email}}",
  "metadata": {
    "source": "workflow",
    "timestamp": "{{step_2.output.timestamp}}"
  }
}

Use placeholders within the JSON to insert dynamic values from previous steps. The Content-Type header is automatically set to application/json when a body is provided.

Retry Attempts

Configure automatic retries for failed requests.

Minimum: 0 (no retries)
Maximum: 3 retries
Default: 0

When retries are enabled, failed requests are automatically retried with exponential backoff (increasing wait time between attempts). Use retries when:

The API occasionally returns temporary errors
Network issues may cause intermittent failures
Rate limiting may temporarily block requests

Output

The block returns the API response data. JSON responses are automatically parsed into objects.

Successful Response

For a successful API call returning JSON:

{
  "id": 12345,
  "name": "John Doe",
  "email": "john@example.com",
  "created_at": "2024-01-15T10:30:00Z"
}

Accessing response data:

{{step_n.output.id}}
{{step_n.output.name}}
{{step_n.output.email}}

For array responses:

[
  {"id": 1, "name": "Item 1"},
  {"id": 2, "name": "Item 2"}
]

Accessing array data:

{{step_n.output[0].name}}
{{step_n.output | size}}

Error Response

When the API returns an error (4xx or 5xx status), the output contains error details:

{
  "error": true,
  "status": 401,
  "message": "Unauthorized",
  "body_preview": "Invalid API key provided..."
}

Non-JSON Response

If the API returns non-JSON content, the raw text is returned as a string:

{{step_n.output}}

Security

The Call API block includes built-in security protections:

HTTPS Only: All requests must use secure HTTPS connections
SSL Verification: Server certificates are validated
Response Size Limit: Maximum 10MB response size
Request Timeout: 30-second timeout for all requests
Safe Redirects: Redirect URLs are validated before following

Best Practices

Store API keys securely and reference them using placeholders
Use appropriate retry settings for unreliable APIs
Check for error responses in subsequent steps before processing data
Set reasonable result limits in query parameters to avoid large responses
Test API calls with sample data before running production workflows
Use GET for reading data, POST for creating or modifying data

Common Use Cases

Use Case	Configuration Tips
CRM integration	POST customer data to Salesforce, HubSpot, etc.
Email service	POST to SendGrid, Mailchimp for transactional emails
Slack notifications	POST workflow results to Slack webhooks
Data enrichment	GET additional data from Clearbit, FullContact
Custom backend	Connect to your own APIs for business logic
Webhook triggers	POST to trigger external automation tools

Example: Slack Notification

Send workflow results to a Slack channel: Method: POST URL: https://hooks.slack.com/services/xxx/yyy/zzz Body:

{
  "text": "Workflow completed!",
  "blocks": [
    {
      "type": "section",
      "text": {
        "type": "mrkdwn",
        "text": "*Results:* {{step_3.output.summary}}"
      }
    }
  ]
}

Example: Fetching Paginated Data

Retrieve data from a paginated API: Method: GET URL: https://api.example.com/items Query Parameters:

Parameter	Value
page	`{{current.page}}`
per_page	`50`

Use with a Loop block to iterate through pages.

Troubleshooting

Error	Cause	Solution
Security violation	Non-HTTPS URL	Change URL to use `https://`
401 Unauthorized	Invalid or missing auth	Check Authorization header value
403 Forbidden	Insufficient permissions	Verify API key has required access
404 Not Found	Invalid endpoint URL	Verify the API endpoint path
429 Too Many Requests	Rate limit exceeded	Add retries or reduce request frequency
Timeout	API too slow	Check if API is responsive, consider async patterns
Invalid JSON	Malformed request body	Validate JSON syntax in body field

What’s Next

Now that you understand the Call API block:

Learn about Loop Block to process paginated API responses
See LLM Block to analyze API response data
Explore Google Sheets Block to store API results
Check Liquid Templating for data transformation

Getting Started

Cowork

Insights

Work

Automate

Assets

Integrations

Overview

Configuration

Request Method

API Endpoint URL

Request Headers

Query Parameters

Request Body

Retry Attempts

Output

Successful Response

Error Response

Non-JSON Response

Security

Best Practices

Common Use Cases

Example: Slack Notification

Example: Fetching Paginated Data

Troubleshooting

What’s Next

​Overview

​Configuration

​Request Method

​API Endpoint URL

​Request Headers

​Query Parameters

​Request Body

​Retry Attempts

​Output

​Successful Response

​Error Response

​Non-JSON Response

​Security

​Best Practices

​Common Use Cases

​Example: Slack Notification

​Example: Fetching Paginated Data

​Troubleshooting

​What’s Next

Overview

Configuration

Request Method

API Endpoint URL

Request Headers

Query Parameters

Request Body

Retry Attempts

Output

Successful Response

Error Response

Non-JSON Response

Security

Best Practices

Common Use Cases

Example: Slack Notification

Example: Fetching Paginated Data

Troubleshooting

What’s Next