Import phone number

Imports a custom phone number into your workspace. This is useful for direct SIP dialing scenarios where your telephony provider does not offer elastic SIP trunking. Set uac_enabled to true when your carrier or PBX requires outbound SIP REGISTER traffic, and optionally set uac_register_expires (60 to 3600 seconds, default 300). For IP-authenticated providers such as zoom, ringcx, five9, and 8x8, termination_uri is filled automatically. For 8x8, omit phone_number to have Synthflow generate the 12-digit identifier required for SIP routing.

Imports a custom phone number into your workspace. This is useful for direct SIP dialing scenarios where your telephony provider does not offer elastic SIP trunking. Set `uac_enabled` to true when your carrier or PBX requires outbound SIP REGISTER traffic, and optionally set `uac_register_expires` (60 to 3600 seconds, default 300). For IP-authenticated providers such as `zoom`, `ringcx`, `five9`, and `8x8`, `termination_uri` is filled automatically. For `8x8`, omit `phone_number` to have Synthflow generate the 12-digit identifier required for SIP routing.

Authentication

AuthorizationBearer

Bearer authentication of the form Bearer <token>, where token is your auth token.

Request

This endpoint expects an object.

workspace_idstringRequired

The workspace ID to associate the phone number with.

phone_numberstringOptional

The phone number to import. Required for most providers. For provider_name=8x8, omit this field to auto-generate the required 12-digit identifier (0-9 only). If supplied, it must contain only digits and be at least 12 digits long.

friendly_namestringOptional

A human-readable name for the phone number.

provider_nameenumOptional

Phone number provider. Use 8x8 for 8x8 Contact Center (SIP domain sip.8x8.com), zoom for Zoom, ringcx for RingCX, five9 for Five9, or omit/custom for a generic SIP trunk.

trunk_usernamestringOptional

Optional SIP trunk username for authentication. Required when uac_enabled is true. Not used for five9, ringcx, or zoom.

trunk_pwdstringOptional

Optional SIP trunk password for authentication. Required when uac_enabled is true. Not used for five9, ringcx, or zoom.

termination_uristringOptional

SIP domain or termination URI used for outbound calls (maps to sip_term_uri). Not required for zoom, ringcx, five9, or 8x8, which set the SIP domain automatically.

sip_outbound_proxystringOptional

Optional outbound proxy used for outbound calls and SIP REGISTER requests. For five9, Synthflow sets the regional TLS proxy automatically when omitted.

sip_auth_usernamestringOptional

Optional auth username used for SIP REGISTER requests when it differs from trunk_username.

uac_enabledbooleanOptionalDefaults to false

When true, Synthflow sends outbound SIP REGISTER traffic to your carrier or PBX so it can authenticate outbound calls. Requires trunk_username and trunk_pwd. Defaults to false.

uac_register_expiresintegerOptional60-3600Defaults to 300

SIP registration refresh interval in seconds. Only used when uac_enabled is true (or for providers that register implicitly, such as RingCentral). Whole numbers only, between 60 and 3600. Defaults to 300.

Response

200

statusstringOptional

Whether the request was successful.

responseobjectOptional

Errors

400

Bad Request Error

403

Forbidden Error

$	curl -X POST https://api.synthflow.ai/v2/custom-numbers \
>	-H "Authorization: Bearer <token>" \
>	-H "Content-Type: application/json" \
>	-d '{
>	"workspace_id": "1710107690998x536152705164378100",
>	"phone_number": "+33782990580",
>	"friendly_name": "My Custom Number",
>	"provider_name": "custom",
>	"termination_uri": "sip.example.com"
>	}'

1	{
2	"status": "ok",
3	"response": {
4	"key": "787f0c0e-fc83-41b1-bfbe-266727f611a4",
5	"phone_number": "+33782990580"
6	}
7	}