CheckNumber API - Phone Number Verification Service

Welcome to CheckNumber API — a phone number verification and validation service for developers and businesses worldwide.

API Introduction

CheckNumber provides advanced phone number verification APIs that help you validate and verify phone numbers across 20+ platforms in bulk. Whether you need to verify WhatsApp registrations, detect social media accounts, check cryptocurrency exchange users, or query phone carrier information, CheckNumber has you covered.

Typical use cases:

Marketing list cleaning — remove inactive numbers before sending campaigns
Fraud prevention — verify user-provided phone numbers on registration
CRM enrichment — identify which platforms your contacts use
Crypto exchange KYC — cross-check user phone numbers against exchange registrations

Quick Start

1. Get your API Key

2. Submit a batch task

Upload a .txt or .csv file with one phone number per line (E.164 format, e.g. +8613800138000):

curl --location 'https://api.checknumber.ai/v1/tasks' \
--header 'X-API-Key: YOUR_API_KEY' \
--form 'file=@"./numbers.txt"' \
--form 'task_type="ws"'

3. Poll for results

curl --location 'https://api.checknumber.ai/v1/gettasks' \
--header 'X-API-Key: YOUR_API_KEY' \
--form 'task_id="TASK_ID_FROM_STEP_2"'

When status becomes exported, download the result file from result_url.

API Overview

Item	Details
Base URL	`https://api.checknumber.ai`
Authentication	`X-API-Key` header
Submit task	`POST /v1/tasks` (multipart/form-data)
Query status	`POST /v1/gettasks` (form-data)
Check balance	`GET /v1/balance`
File format	`.txt` or `.csv`, one entry per line
Max batch size	1,000,000 entries per task

Authentication

All requests require your API key passed in the request header:

X-API-Key: YOUR_API_KEY

Task Status

Status	Meaning
`pending`	Task queued, waiting to start
`processing`	Task is being processed
`exported`	Results ready, download from `result_url`

API Reference

Products are grouped into platforms & email (mixed), cryptocurrency exchange, number & email detection, and carrier filter categories.

Platforms & email

Phone-number tasks and email tasks are listed in the same sequence as the marketing site (Telegram → WhatsApp → … → Netflix / Spotify email).

API	task_type	Description
Telegram Checker	`tg`	Telegram account registration check
Telegram Activity Checker	`tg_active`	Telegram last online days
Telegram Age & Gender Checker	`tg_avatar`	Telegram avatar, age, gender analysis

API	task_type	Description
WhatsApp Checker	`ws`	Bulk WhatsApp registration check
WhatsApp Activity Checker	`ws_active`	Last online days, business status, signature
Whatsapp Age & Gender Checker	`ws_avatar`	Avatar, age, gender, skin color analysis
Phone Number Validation	`phoneCheck`	Bulk format / validity / numbering checks

More platforms & email

API	task_type	Description
Facebook Checker	`facebook`	Facebook account verification
Facebook Email Checker	`facebook_email`	Facebook account check by email
Apple Checker	`apple`	Apple account check by phone number
Apple Email Checker	`apple_email`	Apple account check by email
iMessage Checker	`imessage`	iMessage (Apple) activation check
Rcs Checker	`rcs`	RCS (Rich Communication Services) support check
Instagram Checker	`instagram`	Instagram account verification
Instagram Email Checker	`instagram_email`	Instagram account check by email
Amazon Checker	`amazon`	Amazon account check by phone number
Amazon Email Checker	`amazon_email`	Amazon account check by email
Airbnb Checker	`airbnb`	Airbnb account check by phone number
Twitter Checker	`twitter`	Twitter account verification
Twitter/X Email Checker	`twitter_email`	Twitter/X account check by email
Line Checker	`line`	Line account registration check
Microsoft Checker	`microsoft`	Microsoft account check by phone number
Band Checker	`band`	Band account registration check
GoTo Checker	`goto`	GoTo account registration check
Threads Checker	`threads`	Threads account registration check
Indiatimes Checker	`indiatimes`	Indiatimes account registration check
HT Checker	`ht`	HT account registration check
Cian Checker	`cian`	Cian account registration check
Signal Checker	`signal`	Signal account registration check
Snapchat Checker	`snapchat`	Snapchat account registration check
Messenger Checker	`messenger`	Messenger account registration check
MAX Checker	`max`	MAX messenger registration check
MAX Full Profile Checker	`max_full`	MAX messenger full profile (name, gender, last seen, avatar)
Viber Checker	`viber`	Viber account registration check
Viber Activity Checker	`viber_active`	Viber last online days
Zalo Checker	`zalo`	Zalo account registration check
Netflix Checker	`netflix`	Netflix account check by phone number
Netflix Email Checker	`netflix_email`	Netflix account check by email
Spotify Email Checker	`spotify_email`	Spotify account check by email

Cryptocurrency Exchange Detection

Exchange phone checks, then each exchange’s email check.

API	task_type	Description
Binance Checker	`Binance`	Binance registered account check
Binance Email Checker	`binance_email`	Binance account check by email
Kucoin Checker	`Kucoin`	KuCoin registered account check
Kucoin Email Checker	`kucoin_email`	KuCoin account check by email
CoinW Checker	`coinW`	CoinW registered account check
CoinW Email Checker	`coinw_email`	CoinW account check by email
Htx Checker	`htx`	HTX (Huobi) registered account check
Htx Email Checker	`htx_email`	HTX account check by email
Robinhood Email Checker	`robinhood_email`	Robinhood account check by email
Crypto.com Email Checker	`crypto_email`	Crypto.com account check by email

Number & Email Detection

Phone number activity, high-value user signal, and email validity detection.

API	task_type	Description
Number Active Check	`active_check`	Phone number activity level detection
High Value Users Checker	`high_value_users`	High-value user signal detection by phone number
Email Check	`email_check`	Bulk email address validity check

Carrier Detection

Identify phone number carriers and regional information.

API	task_type	Description
Carrier Detection	`usaCarrier`	Phone number carrier, region, type lookup

Account Management

Manage your CheckNumber account and monitor usage.

API	Method	Description
Balance Query API	`GET /v1/balance`	Query available account balance