Email Deliverability Checker API

Choose one task type per upload: email_check for Deliverability Checker or email_avatar for Avatar Checker. Both use the asynchronous batch workflow below.

Deliverability Checker (email_check)

Check whether email addresses are active and able to receive mail. Only supports Gmail, Yandex, Mail.ru, iCloud, Outlook, and Yahoo.

Avatar Checker (email_avatar)

Check whether email addresses have a public avatar and return the avatar URL. Only supports Gmail, Yandex, and Mail.ru.

Addresses outside the supported providers and their supported alias domains are excluded from processing, results, and billing.

Input format

Upload a text file with one supported email address per line.

user@gmail.com
another@yandex.com

Create a task

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

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

Avatar Checker (email_avatar)

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

The API returns a task ID. Keep this ID and use it to poll the task status.

Upload response

{
  "task_id": "d4g8o46p2jvh04o9uolg",
  "status": "pending",
  "total": 5000,
  "estimated_amount": {
    "amount": "0.500000",
    "currency": "USD"
  },
  "message": "Task created successfully"
}

Check task status

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

curl --location 'https://api.checknumber.ai/v1/gettasks' \
--header 'X-API-Key: YOUR_API_KEY' \
--form 'task_id="d4g8o46p2jvh04o9uolg"'

Poll until status becomes exported. Do not treat pending or processing as a completed result.

Processing response

{
  "task_id": "d4g8o46p2jvh04o9uolg",
  "status": "processing",
  "total": 5000,
  "success": 2500,
  "failure": 0
}

Exported response

{
  "task_id": "d4g8o46p2jvh04o9uolg",
  "status": "exported",
  "total": 5000,
  "success": 5000,
  "failure": 0,
  "result_url": "https://example-link-to-results.zip",
  "actual_amount": {
    "amount": "2.000000",
    "currency": "USD"
  }
}

Result Fields

Deliverability Checker (email_check)

Field	Description	Example
email	Input email address from the submitted file.	user@gmail.com
activated	Whether the input was detected as active or registered.	yes

Avatar Checker (email_avatar)

Field	Description	Example
email	Input email address from the submitted file.	user@gmail.com
activated	Whether the address has a public avatar.	yes
avatar	Avatar image URL when available; empty when the account uses a default placeholder.	https://…
name	Display name when the provider exposes one; otherwise empty.	John Doe

Result file handling

Download the file from result_url only after the task is exported. Preserve the returned column names when processing the file downstream.

Response fields

Field	Description
created_at	Timestamp when the task was created.
updated_at	Timestamp of the latest task status update.
task_id	Unique task identifier.
status	pending, processing, exported, or failed.
total	Total input values processed.
success	Values processed successfully.
failure	Values that failed processing.
result_url	Download URL when the task is exported.
actual_amount	Final settled amount, when available.
estimated_amount	Estimated amount returned when the task is created.

Status codes

Status	Description
200	Request successful.
202	Task created successfully and estimated charge applied.
400	Invalid file, unsupported task type, or too few valid entries.
401	Missing or invalid API key.
402	Insufficient account balance.
403	Product not available for your account (discontinued or whitelist-only); contact support.
404	Task not found.
413	Uploaded file is too large.
500	Internal server error; retry later.
503	Product temporarily unavailable (paused for maintenance); nothing is charged, retry later.

Operational notes

• The task is asynchronous; use the task ID for status polling.
• Check product-specific input limits before uploading.
• Failed rows are reported in the exported result and reflected in the task counters.
• The fields above are based on the current live sample and may change when the upstream export schema changes.