WhoCalled.in

Developer Phone Lookup & Caller ID API

Integrate real-time caller intelligence into your platform. Use the phone number lookup API to enrich contact data, identify telecom operators, and verify mobile circle details inside your applications.

Real-time Caller Intelligence & Enrichment API

Our API is built for CRM systems, lead validation, fraud detection, and customer support desks. Query mobile numbers programmatically to retrieve structured JSON containing circle codes, operator ranges, and name signals.

API Features:

Fast Latency: Target API response times under 5ms.
Simple JSON Payload: Input a phone number and get structured details instantly.
Developer Documentation: Easy integrations for Node.js, Python, PHP, and Go.

Integration Example

Developers can query the lookup endpoint using a simple HTTP POST request. Read our documentation to set up rate limiting, API key authentication, and client integrations.

Embed Backlink & Developer Badge

Building a app, SaaS, or fraud detection dashboard? Show your users that your caller verification is powered by WhoCalled.in by embedding our verified API badge:

Preview of Developer Badge

Copy HTML Embed Code:

<a href="https://whocalled.in/phone-number-lookup-api" target="_blank" rel="noopener" title="Verified by WhoCalled.in Caller ID API"><img src="https://whocalled.in/badge-verified.svg" alt="WhoCalled.in Caller ID API Badge" width="210" height="38" /></a>

Compliance Disclaimer: The Developer API is subject to rate-limiting and terms of service. It must be used in compliance with data protection laws. Do not use lookup data for unsolicited spam marketing.

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Frequently Asked Questions

How can I integrate the phone lookup API?

Submit a POST request to our API search endpoint with the phone number query. The endpoint returns structured JSON data containing carrier and circle info.

What is the query rate limit?

Standard developer accounts are subject to rate limiting to prevent abuse. Premium API keys can be requested for higher volumes.

Is the API suitable for fraud detection?

Yes, verifying telecom operator circle signals is a helpful indicator for fraud screening and customer onboarding workflows.

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