Bulk Email Checker API: Gmail, Outlook, Yahoo & More

Verify which email addresses in your uploaded list are registered on Gmail, Outlook, Yahoo, Mail.ru, or iCloud. Uses task_type email_check and the same batch polling flow as other checkers.

Upload detection file — example:

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

Check task status — example:

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

Response after upload succeeds

{
    "task_id": "d4g8o46p2jvh04o9uolg",
    "status": "pending",
    "total": 2000,
    "estimated_amount": {
        "amount": "0.500000",
        "currency": "USD"
    },
    "message": "Task created successfully",
    "created_at": "2025-11-21T15:58:08.916446594Z"
}

Response while processing

{
    "created_at": "2025-11-21T08:27:09.933Z",
    "updated_at": "2025-11-21T08:27:10.241Z",
    "task_id": "d4g24nep2jvh04o9uoh0",
    "user_id": "wfi7wGPS4B4PdtTMox5Y",
    "status": "processing",
    "total": 2000,
    "success": 800,
    "failure": 0
}

Response when finished (exported)

{
    "created_at": "2025-11-21T08:27:09.933Z",
    "updated_at": "2025-11-21T08:27:10.241Z",
    "task_id": "d4g24nep2jvh04o9uoh0",
    "user_id": "wfi7wGPS4B4PdtTMox5Y",
    "status": "exported",
    "total": 2000,
    "success": 2000,
    "failure": 0,
    "result_url": "https://example-link-to-results.zip",
    "actual_amount": {
      "amount": "2.000000",
      "currency": "USD"
    }
}

Upload file request URL

POST https://api.checknumber.ai/v1/tasks

Upload file request parameters

Parameter	Description
file	file, one email address per line
task_type	string, set to email_check

Check task status request URL

POST https://api.checknumber.ai/v1/gettasks

Check task status request parameters

Parameter	Description
task_id	string, Task ID returned from task creation

Result fields

The result ZIP contains separate files per email provider. Each row includes:

Field	Description
Email	Email address
Active	Whether the email is registered on the platform (true / false)
Provider	Detected email provider: gmail, outlook, yahoo, mailru, icloud, or unsupported

Supported providers

Provider	task_type sub-task
Gmail	email_gmail
Outlook	email_outlook
Yahoo	email_yahoo
Mail.ru	email_mailru
iCloud	email_icloud

Minimum batch size: 2,000 email addresses per task.

Response format

Field	Description
created_at	Timestamp when task was created
updated_at	Timestamp of last task status update
task_id	Unique task identifier
user_id	User ID
status	pending · processing · exported · failed (refunded automatically)
total	Total emails submitted
success	Emails successfully checked
failure	Rows that could not be processed
result_url	Download URL when status is exported
actual_amount	(Optional) Actual charged amount, returned after the task is settled
estimated_amount	(Create response) Estimated amount for the task; the final charge is settled when the task completes

Status codes

Status	Description
200	free, Request successful (e.g. status query)
202	charge, Task created successfully; the estimated amount is deducted
400	free, Bad request: invalid parameters or file format, unsupported task type, or fewer valid entries than the minimum batch size
401	free, Missing or invalid API key
402	free, Insufficient account balance
404	free, Task not found
413	free, Uploaded file too large
500	free, Internal server error, retry later