curl --request POST \
--url https://api.withallo.com/v2/api/dialing-queues/current/numbers \
--header 'Authorization: <api-key>' \
--header 'Content-Type: application/json' \
--data '
{
"numbers": [
{
"number": "+1 (212) 555-0010",
"name": "John",
"last_name": "Doe",
"company": "Acme Inc",
"job_title": "Sales Manager",
"emails": [
"[email protected]"
],
"website": "https://acme.com",
"custom_attributes": {
"lead_source": "Webinar"
}
},
{
"number": "+33 6 12 34 56 78",
"name": "Marie",
"last_name": "Dupont",
"company": "Acme Inc"
},
{
"number": "+44 20 7946 0958"
}
]
}
'{
"data": {
"added": [
{
"number_to": "+12125550010",
"position": 0,
"created_at": "2026-04-30T10:00:00",
"updated_at": "2026-04-30T10:00:00"
},
{
"number_to": "+33612345678",
"position": 1,
"created_at": "2026-04-30T10:00:00",
"updated_at": "2026-04-30T10:00:00"
}
],
"skipped": [],
"ignored_custom_attributes": []
}
}{
"error": {
"type": "validation_error",
"code": "DIALING_QUEUE_LIMIT_REACHED",
"message": "The dialing queue cannot exceed 25,000 numbers.",
"retryable": false
}
}{
"error": {
"type": "<string>",
"code": "<string>",
"message": "<string>",
"retryable": true,
"request_id": "<string>",
"retry_after_seconds": 123
}
}{
"error": {
"type": "not_found_error",
"code": "ASSIGNEE_NOT_FOUND",
"message": "No team member found for the provided 'user_id' or 'email'.",
"retryable": false,
"suggestion": "List your teammates with GET /v2/api/users and use one of their ids as 'user_id', or pass a team-member email."
}
}{
"error": {
"type": "conflict_error",
"code": "DIALING_QUEUE_APPEND_CONFLICT",
"message": "A concurrent append to this queue caused a position conflict.",
"retryable": false,
"suggestion": "Retry the request — the conflict resolves on the next attempt."
}
}{
"error": {
"type": "<string>",
"code": "<string>",
"message": "<string>",
"retryable": true,
"request_id": "<string>",
"retry_after_seconds": 123
}
}Power Dialer
Append numbers
Appends phone numbers to the Power Dialer queue assigned to the authenticated user. Creates the queue implicitly if none exists. Send user_id or email to append to a teammate’s queue — if that teammate has no current queue, one is created with the API key owner as creator_id and the teammate as assignee_id. user_id wins when both are provided.
POST
/
v2
/
api
/
dialing-queues
/
current
/
numbers
curl --request POST \
--url https://api.withallo.com/v2/api/dialing-queues/current/numbers \
--header 'Authorization: <api-key>' \
--header 'Content-Type: application/json' \
--data '
{
"numbers": [
{
"number": "+1 (212) 555-0010",
"name": "John",
"last_name": "Doe",
"company": "Acme Inc",
"job_title": "Sales Manager",
"emails": [
"[email protected]"
],
"website": "https://acme.com",
"custom_attributes": {
"lead_source": "Webinar"
}
},
{
"number": "+33 6 12 34 56 78",
"name": "Marie",
"last_name": "Dupont",
"company": "Acme Inc"
},
{
"number": "+44 20 7946 0958"
}
]
}
'{
"data": {
"added": [
{
"number_to": "+12125550010",
"position": 0,
"created_at": "2026-04-30T10:00:00",
"updated_at": "2026-04-30T10:00:00"
},
{
"number_to": "+33612345678",
"position": 1,
"created_at": "2026-04-30T10:00:00",
"updated_at": "2026-04-30T10:00:00"
}
],
"skipped": [],
"ignored_custom_attributes": []
}
}{
"error": {
"type": "validation_error",
"code": "DIALING_QUEUE_LIMIT_REACHED",
"message": "The dialing queue cannot exceed 25,000 numbers.",
"retryable": false
}
}{
"error": {
"type": "<string>",
"code": "<string>",
"message": "<string>",
"retryable": true,
"request_id": "<string>",
"retry_after_seconds": 123
}
}{
"error": {
"type": "not_found_error",
"code": "ASSIGNEE_NOT_FOUND",
"message": "No team member found for the provided 'user_id' or 'email'.",
"retryable": false,
"suggestion": "List your teammates with GET /v2/api/users and use one of their ids as 'user_id', or pass a team-member email."
}
}{
"error": {
"type": "conflict_error",
"code": "DIALING_QUEUE_APPEND_CONFLICT",
"message": "A concurrent append to this queue caused a position conflict.",
"retryable": false,
"suggestion": "Retry the request — the conflict resolves on the next attempt."
}
}{
"error": {
"type": "<string>",
"code": "<string>",
"message": "<string>",
"retryable": true,
"request_id": "<string>",
"retry_after_seconds": 123
}
}Targeting a teammate’s queue
By default, numbers are appended to the queue assigned to the API key owner. To append to a teammate’s queue, senduser_id or email in the JSON body. The teammate must belong to the same team as the API key owner.
user_id— wins when both are provided. Resolve teammate ids viaGET /v2/api/users.email— used only whenuser_idis absent.
creator_id and the teammate as assignee_id. If the resolved user isn’t on your team, the response is 404 ASSIGNEE_NOT_FOUND.
Custom fields
Each number can carrycustom_attributes: values for your team’s person custom fields, keyed by field key. List the keys with GET /v2/api/crm/attributes. The values are written on the contact behind the number, and the contact is created if the number has none.
{
"numbers": [
{
"number": "+12125550010",
"name": "John",
"custom_attributes": {
"lead_source": "Webinar",
"deal_size": "1200",
"next_meeting": "2026-11-03"
}
}
]
}
| Field type | Value |
|---|---|
TEXT | Any text |
NUMBER | A number, such as 1200 or 12.5 |
DATE | YYYY-MM-DD or an ISO date-time, or a day, month and 4-digit year separated by /, - or ., such as 03/04/2026 |
BOOLEAN | true/false, 1/0, yes/no, y/n or oui/non, in any case |
DROPDOWN | The label or key of one of the field’s options |
Date order
03/04/2026 is 3 April in Europe and 4 March in the US. Send date_order next to numbers to say which one you mean: DAY_FIRST or MONTH_FIRST. It applies to every date field in the request.
{
"date_order": "MONTH_FIRST",
"numbers": [
{ "number": "+12125550010", "custom_attributes": { "next_meeting": "11/03/2026" } }
]
}
date_order, each date field is read in the order its own values settle: 13/04/2026 can only be day first, 04/13/2026 only month first. When the values don’t settle it, the country of your phone number decides: month first for the US, day first everywhere else.
Blank values are ignored. When the contact already exists, only its empty fields are filled: a value already set is kept.
Custom fields are never created by this endpoint. Create them first with POST /v2/api/crm/attributes.
A key that matches none of your team’s custom fields, or names a deleted field, is ignored. The number is still added with its known attributes, and the unknown keys are listed in ignored_custom_attributes: an always-present array of { "number", "keys" } entries, with number in E.164 format. The array is empty when no key was ignored.
{
"added": [{ "number_to": "+12125550010", "position": 0 }],
"skipped": [],
"ignored_custom_attributes": [
{ "number": "+12125550010", "keys": ["unknown_field"] }
]
}
skipped:
reason | Meaning |
|---|---|
INVALID_CUSTOM_ATTRIBUTE_VALUE | A value does not fit its field type: soon or 31/02/2026 for a DATE field, a 2-digit year such as 03/04/26, maybe for a BOOLEAN field |
Authorizations
Body
application/json
Numbers to append to the queue. Each entry requires a phone number; contact metadata is optional.
Minimum array length:
1Show child attributes
Show child attributes
Optional. ID of a teammate whose queue should receive the numbers. The teammate must belong to the same team as the API key owner. Wins over email when both are provided. Resolve teammate ids via GET /v2/api/users.
Example:
"usr-15BB68317A7F06F0C07A3BBD8F244102A6872220"
Optional. Email of a teammate whose queue should receive the numbers. Ignored when user_id is also supplied.
Example:
Optional. How to read numeric DATE values in custom_attributes such as 03/04/2026: DAY_FIRST (3 April) or MONTH_FIRST (4 March). Applies to every date field in the request. When absent, each date field is read in the order its values settle (a 13/04/2026 can only be day first); when none settle it, your phone number's country decides: month first for the US, day first everywhere else.
Available options:
DAY_FIRST, MONTH_FIRST Example:
"DAY_FIRST"
Response
Numbers appended
Show child attributes
Show child attributes
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