CheckNumber API - Phone Number Verification & Validation Service
CheckNumber API Documentation
Welcome to CheckNumber API — the leading phone number verification and validation service for developers and businesses worldwide.
What is CheckNumber?
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
Sign up at checknumber.ai and retrieve your API key from the dashboard.
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_KEYTask Status
| Status | Meaning |
|---|---|
pending | Task queued, waiting to start |
processing | Task is being processed |
exported | Results ready, download from result_url |
API Reference
1. WhatsApp
Our WhatsApp APIs verify account registration, detect active users, analyze avatars, and identify business accounts.
| API | task_type | Description |
|---|---|---|
| WhatsApp Realtime Checker | — | Single number real-time check |
| WhatsApp Bulk Number Checker | ws | Bulk WhatsApp registration check |
| WhatsApp Bulk Number Checker Avatar (Age and Gender) | ws_avatar | Avatar, age, gender, skin color analysis |
| WhatsApp Days Checker | ws_active | Last online days, business status, signature |
2. Social Media
| API | task_type | Description |
|---|---|---|
| Instagram Bulk Number Checker | instagram | Instagram account verification |
| Facebook Bulk Number Checker | facebook | Facebook account verification |
| Twitter Bulk Number Checker | twitter | Twitter account verification |
| LinkedIn Bulk Number Checker | linkedIn | LinkedIn account verification |
3. Messaging Platforms
| API | task_type | Description |
|---|---|---|
| Telegram Bulk Number Checker | tg | Telegram account registration check |
| Telegram Days Checker | tg_active | Telegram last online days |
| Telegram Bulk Number Checker Avatar (Age and Gender) | tg_avatar | Telegram avatar, age, gender analysis |
| Zalo Bulk Number Checker | zalo | Zalo account registration check |
| Viber Bulk Number Checker | viber | Viber account registration check |
| Viber Activity Checker | viber_active | Viber last online days |
| Viber Bulk Number Checker Avatar (Age and Gender) | viber_senior | Viber avatar, age, gender analysis |
| Line Bulk Number Checker | line | Line account registration check |
| iMessage Bulk Number Checker | imessage | iMessage (Apple) activation check |
4. Cryptocurrency Exchanges
| API | task_type | Description |
|---|---|---|
| Binance Bulk Number Checker | Binance | Binance registered account check |
| KuCoin Bulk Number Checker | Kucoin | KuCoin registered account check |
| CoinW Bulk Number Checker | coinW | CoinW registered account check |
| HTX Bulk Number Checker | htx | HTX (Huobi) registered account check |
| MEXC Bulk Number Checker | mexc | MEXC registered account check |
5. Email Checkers
| API | task_type | Description |
|---|---|---|
| Netflix Bulk Email Checker | netflix | Netflix account check by email |
| Apple Email Checker | apple_email | Apple account check by email |
| Amazon Email Checker | amazon_email | Amazon account check by email |
| Facebook Email Checker | facebook_email | Facebook account check by email |
| MEXC Email Checker | mexc_email | MEXC account check by email |
6. Other Services
| API | task_type | Description |
|---|---|---|
| Apple Bulk Number Checker | apple | Apple account check by phone number |
| Amazon Bulk Number Checker | amazon | Amazon account check by phone number |
| Microsoft Bulk Number Checker | microsoft | Microsoft account check by phone number |
| RCS Checker | rcs | RCS (Rich Communication Services) support check |
| Global Phone Carrier Inquiry | — | Phone number carrier, region, type lookup |
7. Account Management
| API | Method | Description |
|---|---|---|
| Balance Query API | GET /v1/balance | Query available account balance |