International Calling Setup

Overview

Calling internationally introduces two things you need to get right beyond a standard domestic setup: strict phone number formatting, and getting an international-capable number onto your account in the first place, since the platform's free numbers are US-only. This page covers both, plus how outbound routing and dialing concurrency behave once international numbers are in play — cross-referencing the Outbound Campaigns and SIP Trunking pages for the deeper setup steps each touches on.

Every phone number used for calling — recipient numbers, your own registered numbers, and CSV recipient lists for campaigns — must be in E.164 format, the international standard for phone numbers:

• A + prefix
• Country code followed by the subscriber number, including area code
• Maximum 15 digits total
• No spaces, dashes, or other special characters

Example: +14151234567. This applies universally, not just to international numbers — but it becomes more visible with international calling since you're no longer just prepending a familiar domestic area code.

numberE164CheckEnabled controls whether the platform strictly validates E.164 formatting on a phone number. It appears in two places:

• When registering or importing a number (via the phone-number endpoint) — controls whether that number must be valid E.164 to be accepted
• On the customer object for an outbound call — controls whether the destination number for that specific call is validated

{
  "customer": {
    "number": "+14155550123",
    "numberE164CheckEnabled": true
  }
}

Setting it to true enforces strict validation; setting it to false allows non-standard formats through, which is sometimes necessary for edge cases like extension-style destinations or certain SIP-only routing scenarios. When in doubt, leave it enabled and fix the underlying number format instead of disabling the check.

The platform's free, dashboard-provisioned phone numbers are US national use only. If you need an international number, you have two options:

• Import your own number — bring in a number you already manage from your phone number provider that supports the country you need
• Use a BYO SIP trunk — connect any SIP carrier that offers coverage in your target country or region, which gives you full control over inbound and outbound routing for that number

See the SIP Trunking page for the full BYO SIP trunk setup, and the Outbound Campaigns page for how imported and BYO numbers plug into a campaign once registered.

When placing outbound calls over a BYO SIP trunk, the outboundLeadingPlusEnabled field on the trunk credential controls whether the leading + is preserved when the number is sent to your carrier:

{
  "provider": "byo-sip-trunk",
  "name": "My International Trunk",
  "gateways": [{ "ip": "YOUR_PROVIDER_IP", "outboundEnabled": true }],
  "outboundLeadingPlusEnabled": true,
  "outboundAuthenticationPlan": {
    "authUsername": "YOUR_SIP_USERNAME",
    "authPassword": "YOUR_SIP_PASSWORD"
  }
}

Whether this should be true or false depends entirely on how your specific carrier expects to receive international PSTN destinations — some require the leading +, others expect it stripped. Check your carrier's SIP trunking documentation for their expected dialing format, and set this field to match; a mismatch here is a common cause of otherwise-valid international calls failing to route.

The platform's outbound dialing mechanism for large recipient lists is the Dashboard's Outbound Campaigns feature, which dials from a CSV recipient list at a concurrency determined by your account's call concurrency limit — the same mechanism whether recipients are domestic or international. For international campaigns specifically:

• Every number in your recipient CSV must be in valid E.164 format with the correct country code — numbers that fail validation will fail outright and drag down your campaign's pickup rate
• If your international numbers route through a BYO SIP trunk, confirm outboundLeadingPlusEnabled and your trunk's gateway configuration are correct before launching a campaign at volume, since a routing misconfiguration will affect every call in the batch, not just one
• Concurrency limits apply per account, not per country — a campaign mixing domestic and international recipients shares the same concurrency pool

See the Outbound Campaigns page for the full campaign creation workflow and CSV formatting rules, and the Call Concurrency Limits page for how concurrency is determined for your account.