API Docs

WhatsApp verification API for single and batch checks

Choose a service type for a single check or submit up to 100 numbers in one batch request, with synchronous results in both cases.

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API endpointPOST

/api/v1/check

X-API-Keycode · msg · data

Last updated: August 14, 20263 service typesregistration · avatar · Business

API at a glanceSingle, batch, and balance endpoints share one API-key contract, with a consistent code / msg / data response envelope.

Quickstart

1.Create an API key in Settings.
2.Use GET /api/v1/balance to check the current balance before a batch.
3.POST one phone number to /api/v1/check, or up to 100 numbers to /api/v1/batch-check.
4.Read data.registered and the product-specific fields in the response.

Authentication

Use an API key created in Settings and send it with every request.

X-API-Key: sk_your_api_key

Keep your API key secret

Always call this endpoint from your server. Anyone holding the key can spend your balance.

Products and result fields

wsWhatsApp Registration CheckConfirm whether a phone number is registered on WhatsApp.

ws_avatarWhatsApp Avatar CheckCheck registration, whether the WhatsApp account has set an avatar, and return the avatar URL when available.

ws_businessWhatsApp Business Account CheckCheck registration and identify whether the number uses a WhatsApp Business account.

ws

WhatsApp Registration Check

Confirm whether a phone number is registered on WhatsApp.

Single check

curl -X POST "https://walookup.com/api/v1/check" \
  -H "X-API-Key: sk_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{ "service_type": "ws", "identifier": "+14155552671" }'

Registered

{
  "code": 0,
  "msg": "ok",
  "data": {
    "service_type": "ws",
    "identifier": "+14155552671",
    "registered": true
  }
}

Not registered

{
  "code": 0,
  "msg": "ok",
  "data": {
    "service_type": "ws",
    "identifier": "+14155550000",
    "registered": false
  }
}

FieldTypeDescription

registeredbooleanWhether the number is registered on WhatsApp.

Batch

Pricing: per number

Each number in the payload is billed independently. Maximum 100 numbers per request. Only successfully checked numbers consume balance. The request is rejected before processing if your balance cannot cover the full batch.

Submit up to 100 numbers in one request; results are returned in the same order.

curl -X POST "https://walookup.com/api/v1/batch-check" \
  -H "X-API-Key: sk_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{ "service_type": "ws", "identifiers": ["+14155552671", "+14155550000"] }'

{
  "code": 0,
  "msg": "ok",
  "data": {
    "service_type": "ws",
    "total": 2,
    "succeeded": 1,
    "failed": 1,
    "results": [
      {
        "identifier": "+14155552671",
        "exists": true,
        "registered": true
      },
      {
        "identifier": "+14155550000",
        "exists": false
      }
    ]
  }
}

FieldTypeDescription

existsbooleanWhether this number produced a result. false means it failed or couldn't be determined — a bad number, an undetermined result, or a momentary limit; when false, none of the fields below are present.

registeredbooleanWhether the number is registered. Present only when exists is true, with the same meaning as the single check.

ws_avatar

WhatsApp Avatar Check

Check registration, whether the WhatsApp account has set an avatar, and return the avatar URL when available.

Single check

curl -X POST "https://walookup.com/api/v1/check" \
  -H "X-API-Key: sk_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{ "service_type": "ws_avatar", "identifier": "+14155552671" }'

Registered

{
  "code": 0,
  "msg": "ok",
  "data": {
    "service_type": "ws_avatar",
    "identifier": "+14155552671",
    "registered": true,
    "avatar": true,
    "avatar_url": "https://pps.waavatar.xyz/v/example.jpg"
  }
}

Not registered

{
  "code": 0,
  "msg": "ok",
  "data": {
    "service_type": "ws_avatar",
    "identifier": "+14155550000",
    "registered": false,
    "avatar": false,
    "avatar_url": ""
  }
}

FieldTypeDescription

registeredbooleanWhether the number is registered on WhatsApp.

avatarbooleanWhether the WhatsApp account has set an avatar.

avatar_urlstringThe avatar URL, returned when an avatar is set and available.

Batch

Pricing: per number

Submit up to 100 numbers in one request; results are returned in the same order.

curl -X POST "https://walookup.com/api/v1/batch-check" \
  -H "X-API-Key: sk_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{ "service_type": "ws_avatar", "identifiers": ["+14155552671", "+14155550000"] }'

{
  "code": 0,
  "msg": "ok",
  "data": {
    "service_type": "ws_avatar",
    "total": 2,
    "succeeded": 1,
    "failed": 1,
    "results": [
      {
        "identifier": "+14155552671",
        "exists": true,
        "registered": true,
        "avatar": true,
        "avatar_url": "https://pps.waavatar.xyz/v/example.jpg"
      },
      {
        "identifier": "+14155550000",
        "exists": false
      }
    ]
  }
}

FieldTypeDescription

registeredbooleanWhether the number is registered. Present only when exists is true, with the same meaning as the single check.

avatarbooleanWhether the WhatsApp account has set an avatar.

avatar_urlstringThe avatar URL, returned when an avatar is set and available.

ws_business

WhatsApp Business Account Check

Check registration and identify whether the number uses a WhatsApp Business account.

Single check

curl -X POST "https://walookup.com/api/v1/check" \
  -H "X-API-Key: sk_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{ "service_type": "ws_business", "identifier": "+14155552671" }'

Registered

{
  "code": 0,
  "msg": "ok",
  "data": {
    "service_type": "ws_business",
    "identifier": "+14155552671",
    "registered": true,
    "business": true
  }
}

Not registered

{
  "code": 0,
  "msg": "ok",
  "data": {
    "service_type": "ws_business",
    "identifier": "+14155550000",
    "registered": false,
    "business": false
  }
}

FieldTypeDescription

registeredbooleanWhether the number is registered on WhatsApp.

businessbooleanWhether the account is a WhatsApp Business account.

Batch

Pricing: per number

Submit up to 100 numbers in one request; results are returned in the same order.

curl -X POST "https://walookup.com/api/v1/batch-check" \
  -H "X-API-Key: sk_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{ "service_type": "ws_business", "identifiers": ["+14155552671", "+14155550000"] }'

{
  "code": 0,
  "msg": "ok",
  "data": {
    "service_type": "ws_business",
    "total": 2,
    "succeeded": 1,
    "failed": 1,
    "results": [
      {
        "identifier": "+14155552671",
        "exists": true,
        "registered": true,
        "business": true
      },
      {
        "identifier": "+14155550000",
        "exists": false
      }
    ]
  }
}

FieldTypeDescription

registeredbooleanWhether the number is registered. Present only when exists is true, with the same meaning as the single check.

businessbooleanWhether the account is a WhatsApp Business account.

Rate limits, concurrency, and retry behavior

Checks are synchronous. Use the returned code to decide whether to accept the result, slow down, or retry later.

200 requests per minuteDashboard and API checks share one UTC fixed-minute window per user. For code 42900, Retry-After is the number of seconds until the next window.
5 concurrent checksA user can run up to five checks at once (a batch request's numbers share this same budget). Code 42901 means all slots are occupied; submit again after an in-flight check finishes.
429 is not chargedRate and concurrency limits reject the request before billing, create no check result, and deduct no balance. The caller may submit again after the relevant limit recovers.
Retry 503 laterA temporary service failure is not a registration result. Keep the input pending and retry later.

Error codes

40000Unsupported service type or conflicting request fields

40001Invalid JSON body

40002Invalid phone number

40100Missing or invalid API key

40200Insufficient balance

42200Upstream could not determine this number. No data is returned and the request is not charged

42900Rate limit exceeded

42901All concurrency slots are occupied; submit after an in-flight request finishes. The rejected request is not charged

50300Validation service maintenance

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