Bulk Phone Status Detection with ZelNum (Webhook) | n8n

Bulk phone status detection via ZelNum—powered by an n8n webhook

This n8n workflow accepts a webhook with 2,000+ phone numbers, submits them to ZelNum Detect for bulk phone status detection, then polls until the async task finishes and returns the ZelNum result download URL in the webhook response.

What this workflow does

• Receives a POST webhook request containing a product slug, a country code, and a phones array.
• Validates the payload and rejects requests if phones is not an array or contains fewer than 2,000 numbers.
• Starts bulk detection by sending the numbers to the ZelNum Detect API, which creates an asynchronous detection task.
• Polls task status using the ZelNum Tasks API every 5 seconds, up to 100 attempts, until the task completes or fails.
• If ZelNum reports failure, the workflow stops and returns the API error message.
• When complete, it calls ZelNum to retrieve and return the result download URL as the webhook response.

Use cases

• Run bulk phone validation for telecom/SMS campaigns and obtain a downloadable results link for downstream processing.
• Automate customer list hygiene by sending large batches of E.164 numbers for ZelNum phone status detection.
• Integrate detection into a SaaS back office workflow—your app posts the batch and receives a URL to fetch results.

Technical details

• n8n nodes/workflow building blocks: Webhook, If, Code, Wait, HTTP Request, Sticky Note.
• Integrations: ZelNum Detect API + ZelNum Tasks API (async polling).
• Auth: add your ZelNum API key to n8n as an HTTP Header Auth credential using header name X-API-Key, and attach it to all ZelNum HTTP requests.
• Input format: POST JSON with product, country, and a phones array of at least 2,000 E.164-formatted numbers.