The Numbers API enables you to search for, view, and activate numbers.

Download the OpenAPI specification here.

Contact Sinch support here: Support@sinch.com


The Numbers API uses client_id and secret to authenticate requests. You can view and manage your API keys here.

Authentication to the API is performed via HTTP Basic Auth. Use your client_id as the basic auth username and your secret as the password.

 --url 'https://numbers.api.sinch.com/v1/projects/{projectId}/availableNumbers?regionCode=US' \
 --header 'Accept: application/json' \
 -u {clientId}:{clientSecret}

We also support OAuth for short lived tokens. To get an OAuth token, you will post your client_id and secret to the Sinch endpoint.

--url 'https://auth.sinch.com/oauth2/token' -d grant_type=client_credentials --user <client_id>:<client_secret>

You then will use the token generated by the above as the bearer in your requests.

Error Codes

The following section details error codes used in SMS Scheduled Provisioning configuration by the Numbers API.

Error CodeDescription
INTERNAL_ERRORInternal error. Please contact Sinch support.
SMS_PROVISIONING_FAILEDThe number could not be added to the specified SMS Serviceplan. Please select a different service plan or contact customer support for assistance.
CAMPAIGN_PROVISIONING_FAILEDThis campaign could not be provisioned. Verify that the campaign is correct or please contact customer support for assistance.
CAMPAIGN_NOT_AVAILABLECampaign not available from TCR. Check the CampaignId provided and ensure Sinch has been selected as the Direct Connection Aggregator (DCA).
EXCEEDED_10DLC_LIMITToo many numbers have been added to this campaign. Please create a new campaign.
NUMBER_PROVISIONING_FAILEDThis number could not be provisioned to the campaign. Please select a new number or contact Sinch.
PARTNER_SERVICE_UNAVAILABLEOne of Sinch's partners is temporarily unavailable, and we are unable to complete the registration at this time. Please try again later.
CAMPAIGN_PENDING_ACCEPTANCESinch has not yet accepted this campaign. Contact your Sinch account manager for assistance.
MNO_SHARING_ERRORCampaign has not been shared with MNO. Verify that all MNOs are selected for the campaign. If so, contact Sinch or create new campaign.