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Duo's main authentication methods — Duo Push and Duo Mobile-generated passcodes — are app-based and have no telephony cost, but require a smartphone or other mobile device. Duo also supports telephony-based authentication via phone calls and SMS messages. Each authentication call or SMS message is debited against your telephony credit balance (as per rate card).
If you ever exhaust your telephony credit balance, your users will not be able to receive authentication phone calls or text messages. They will still be able to authenticate using non-telephony methods: Duo Push, Duo Mobile passcodes, and hardware tokens.
Paid accounts are issued credits yearly, and may purchase extra telephony credits as needed. Duo Free account holders can also purchase additional telephony credits.
There are two types of telephony credits: allowance credits and backup credits. All account holders — even those using free accounts — can purchase backup credits, but only paid accounts are issued allowance credits.
Allowance credits are refilled automatically every year for all paid accounts. Duo Beyond, Duo Access, and Duo MFA plan accounts with automatic billing receive 100 credits per user per year. For example, a customer subscribing to the "Up to 30 users" Duo MFA plan will receive 3,000 Allowance Credits per year. Unused allowance credits do not roll over.
For additional information on telephony credits in Duo's paid plans, please contact us.
Please note that Duo Free plan customers and educational institutions subscribing to any Duo plan do not receive allowance telephony credits.
Backup credits are used if you run out of allowance credits during the year. Purchase backup credits at any time with a 1,000 credit minimum. All customers on all Duo editions may purchase backup credits. Backup credits do not expire, and the unused balance carries forward. Backup credits are used only when no allowance credits are available.
Duo automatically notifies all account administrators when the credit balance falls below a pre-determined percentage of your total credits. You can configure the low-credit alert and set the maximum credits per user authentication in your account's Settings.
Role required: Owner or Billing.
You can check your balances for both types of credits and purchase backup credits using the Telephony Credits page. Here's how:
Log in to the Duo Admin Panel and click Billing in the left sidebar, and then click Telephony Credits in the submenu.
The Telephony Credits page shows your available allowance and backup telephony credits.
For a detailed view of the calls and SMS messages that have debited your account, click the Telephony Logs button in the upper right corner.
To purchase backup credits, enter the number of credits you wish to buy (minimum 1,000) in the "Credits to add" box. The total cost of the credits is calculated and displayed. Click the Purchase Credits button to finish.
A valid credit card must be associated with your account to purchase backup telephony credits. Click Billing then Payment Info in the Duo Admin Panel to add your card information.
You can also access the Telephony Log from the Duo Admin Panel Dashboard:
Log in to the Duo Admin Panel and click Reports in the left sidebar. Click Telephony Log in the Reports submenu.
The Telephony Log page lists SMS and phone events with the associated phone number and telephony credit usage for that event. The log also includes each event's context, or the type of action that triggered the telephony usage. For example, "Authentication" is an end user requesting SMS passcodes or a phone call verification during Duo two-factor login.
At Duo, we’re constantly expanding our international footprint. To do so, we’ve built out infrastructure which guarantees telephony support in a variety of regions.
Customers doing business in the countries below can leverage the following telephony methods:
| Country | Phone Callback | SMS |
|---|---|---|
| Australia | Yes | Yes |
| Brazil | Yes | Yes |
| Canada | Yes | Yes |
| Chile | Yes | Yes |
| Czech Republic | Yes | Yes |
| Denmark | No | Yes |
| Egypt | No | Yes |
| France | Yes | Yes |
| Germany | Yes | Yes |
| India | Yes | Yes (more details) |
| Ireland | No | Yes |
| Italy | No | Yes |
| Japan | Yes | Yes |
| Kenya | No | Yes |
| Kuwait | Yes | Yes |
| Mexico | Yes | Yes |
| Morocco | No | Yes |
| Netherlands | Yes | Yes |
| Nigeria | No | Yes |
| New Zealand | Yes | Yes |
| Norway | No | Yes |
| Poland | No | Yes |
| Puerto Rico | Yes | Yes |
| Saudi Arabia | Yes | Yes |
| Singapore | Yes | Yes |
| South Africa | Yes | Yes |
| Spain | Yes | Yes |
| United Arab Emirates | No | Yes |
| United Kingdom | Yes | Yes |
| United States | Yes | Yes |
The list above includes countries for which Duo has done a reliability audit. A "No" value in the table for a country doesn't mean that method won't function, but that we are not comfortable stating "Yes" for that country and method for a variety of reasons (typically due to phone number expense and/or telephony reliability).
If a country does not appear on the list above it does not mean telephony in the region is unsupported. Absence from the list means that we haven’t completed an audit of the region to ensure it meets our telephony standards. We are proactively expanding our list of supported countries in conjunction with local telco providers.
That being said, in some cases countries have phone numbers that are prohibitively expensive (certain mobile carriers, satellite phones, etc.). These numbers are not supported at this time.
If you have questions about country telephony support, please reach out through your account representative or contact us.
This is the potential rate card associated with supported countries, which includes rate information for countries not yet audited for telephony reliability
Text messages to most areas of the US and Canada cost 1 credit each and phone calls to most areas of US/Canada cost 2 credits each. See the table below for credit charges to other countries.
Note: This rate card is provided as a general guide to telephony costs. Certain individual phone numbers may in fact be more expensive.
| Country | Phone Call | SMS Message |
|---|---|---|
| Australia | 5 / 20 | 5 |
| Brazil | 5 / 30 | 10 |
| Canada | 2 / 30 / 150 | 1 |
| Chile | 5 / 20 / 40 | 10 |
| Czech Republic | 10 / 40 | 10 |
| Denmark | 5 / 20 | 5 |
| Egypt | 30 | 5 |
| France | 5 / 20 | 10 |
| Germany | 5 / 20 / 30 | 10 |
| India | 5 | 5 |
| Ireland | 5 / 20 / 30 | 10 |
| Italy | 5 / 20 / 30 / 40 | 10 |
| Japan | 5 / 30 | 10 |
| Kenya | 20 / 30 | 5 |
| Kuwait | 20 | 5 |
| Mexico | 5 / 10 / 20 | 5 |
| Morocco | N/A | 5 |
| Netherlands | 5 / 10 | 10 |
| New Zealand | 10 | 10 |
| Nigeria | 20 / 30 | 5 |
| Norway | 5 / 30 / 40 | 10 |
| Poland | 5 / 30 | 5 |
| Puerto Rico | 5 | 5 |
| Saudi Arabia | 20 / 30 | 5 |
| Singapore | 5 | 5 |
| South Africa | 10 / 30 | 10 |
| Spain | 5 / 20 | 10 |
| Sweden | 5 / 10 | 10 |
| United Arab Emirates | 30 | 5 |
| United Kingdom | 5 / 30 / 40 | 5 |
| United States | 2 / 5 | 1 |
| Country | Phone Call | SMS Message |
|---|---|---|
| Afghanistan | 50 | 5 |
| Albania | 20 / 50 | 5 |
| Algeria | 10 / 20 / 30 | 10 |
| American Samoa | 20 | 10 |
| Andorra | 10 / 50 | 5 |
| Angola | 30 / 40 | 5 |
| Anguilla | 20 / 40 / 150 | 5 |
| Antigua and Barbuda | 20 | 5 |
| Argentina | 5 / 30 | 10 |
| Armenia | 20 / 40 | 10 |
| Aruba | 20 / 30 / 40 | 10 |
| Austria | 5 / 20 / 50 | 10 |
| Azerbaijan | 40 | 10 |
| Bahamas | 10 / 150 | 5 |
| Bahrain | 30 / 40 / 150 | 5 |
| Bangladesh | 10 | 20 |
| Barbados | 20 / 30 / 40 | 5 |
| Belarus | 50 | 10 |
| Belgium | 5 / 20 | 10 |
| Belize | 40 / 50 | 5 |
| Benin | 40 | 5 |
| Bermuda | 20 / 150 | 5 |
| Bhutan | 30 | 10 |
| Bolivia | 20 / 30 | 10 |
| Bosnia and Herzegovina | 20 / 60 | 5 |
| Botswana | 20 / 40 | 10 |
| Brunei | 10 | 5 |
| Bulgaria | 10 / 60 / 70 | 20 |
| Burkina Faso | 40 | 5 |
| Burundi | 40 | 10 |
| Cambodia | 20 | 5 |
| Cameroon | 30 / 40 | 5 |
| Canary Islands | 5 | N/A |
| Cape Verde | 50 | 5 |
| Cayman Islands | 20 / 30 / 150 | 5 |
| Central African Republic | N/A | 5 |
| Chad | 50 | 5 |
| China | 5 | 10 |
| Colombia | 10 / 20 | 10 |
| Comoros | 90 | 10 |
| Congo | 40 | 10 |
| Cook Islands | N/A | 5 |
| Costa Rica | 10 | 10 |
| Cote D'Ivoire | N/A | 10 |
| Croatia | 10 / 40 | 5 |
| Cuba | N/A | 5 |
| Cyprus | 10 | 20 |
| Djibouti | 60 | 5 |
| Dominica | 40 / 150 | 5 |
| Dominican Republic | 10 / 20 / 30 / 150 | 5 |
| Ecuador | 20 / 40 | 10 |
| El Salvador | 40 | 5 |
| Equatorial Guinea | 40 | 5 |
| Eritrea | 60 | 5 |
| Estonia | 10 / 60 / 90 | 10 |
| Ethiopia | 40 / 50 | 5 |
| Faroe Islands | 40 | 5 |
| Fiji | 60 | 5 |
| Finland | 10 / 20 | 10 |
| French Guiana | 20 / 60 | 10 |
| French Polynesia | 50 | 20 |
| Gabon | 30 / 40 | 5 |
| Gambia | 70 | 5 |
| Georgia | 10 / 30 | 10 |
| Ghana | 20 / 40 | 5 |
| Gibraltar | 20 / 40 / 50 | 5 |
| Greece | 5 / 30 | 10 |
| Greenland | 90 | 5 |
| Grenada | 20 / 30 / 40 / 150 | 5 |
| Guadeloupe | 20 / 50 | 20 |
| Guam | 10 / 130 | 20 |
| Guatemala | 30 | 10 |
| Guinea | 40 | 5 |
| Guinea-Bissau | N/A | 5 |
| Guyana | 40 | 10 |
| Haiti | 30 / 40 | 10 |
| Honduras | 20 / 40 | 10 |
| Hong Kong | 5 | 5 |
| Hungary | 5 / 30 | 10 |
| Iceland | 10 / 40 / 50 | 5 |
| Indonesia | 10 / 20 | 5 |
| Iran | 30 | 5 |
| Iraq | 20 / 30 | 5 |
| Israel | 5 / 20 / 50 | 10 |
| Jamaica | 20 / 30 / 40 / 150 | 5 |
| Jersey | N/A | 5 |
| Jordan | 10 / 20 | 10 |
| Kazakhstan | N/A | 10 |
| Kiribati | N/A | 5 |
| Korea | 5 / 20 | 10 |
| Kyrgyzstan | 20 | 5 |
| Laos | 20 | 5 |
| Latvia | 10 / 40 / 60 | 10 |
| Lebanon | 20 / 30 | 5 |
| Lesotho | 60 | 10 |
| Liberia | 50 | 10 |
| Libya | 50 | 5 |
| Liechtenstein | 10 / 130 | 5 |
| Lithuania | 20 / 40 / 90 | 5 |
| Luxembourg | 5 / 40 | 5 |
| Macau | 10 | 5 |
| Macedonia | 20 / 50 | 5 |
| Madagascar | 50 | 5 |
| Malawi | 30 | 5 |
| Malaysia | 5 / 10 | 5 |
| Maldives | 40 | 5 |
| Mali | 30 / 40 | 5 |
| Malta | 20 / 50 | 5 |
| Martinique | 20 / 60 / 80 | 20 |
| Mauritania | 40 | 5 |
| Mauritius | 30 | 5 |
| Micronesia | 40 | 5 |
| Moldova | 30 / 40 | 10 |
| Monaco | 10 / 50 | 5 |
| Mongolia | 30 | 5 |
| Montenegro | 30 / 50 | 5 |
| Montserrat | 30 / 150 | 5 |
| Mozambique | 30 / 40 | 5 |
| Namibia | 20 / 50 | 5 |
| Nauru | N/A | 5 |
| Nepal | 30 / 40 | 5 |
| Netherlands Antilles | 20 / 30 | 10 |
| New Caledonia | 50 | 5 |
| Nicaragua | 30 / 40 | 5 |
| Niger | 30 | 5 |
| Northern Mariana Islands | 20 / 130 | N/A |
| Oman | 30 | 5 |
| Pakistan | 30 | 5 |
| Palestinian Territory | 50 | 10 |
| Panama | 5 / 10 / 20 | 10 |
| Papua New Guinea | N/A | 5 |
| Paraguay | 20 / 40 | 5 |
| Peru | 5 / 10 / 20 / 40 | 5 |
| Philippines | 30 | 5 |
| Portugal | 5 / 20 | 10 |
| Qatar | 40 | 5 |
| Réunion Island | 50 / 60 | 20 |
| Republic Of The Congo | N/A | 10 |
| Romania | 10 / 30 / 50 | 10 |
| Russia | 5 / 20 / 30 | 5 |
| Rwanda | 20 / 30 | 5 |
| Saint Kitts and Nevis | N/A | 5 |
| Saint Lucia | N/A | 5 |
| Saint Pierre and Miquelon | N/A | 10 |
| Saint Vincent | N/A | 5 |
| Samoa | 70 | 5 |
| San Marino | 10 | 10 |
| Sao Tome and Principe | N/A | 10 |
| Senegal | 30 / 40 | 10 |
| Serbia | 20 / 40 / 50 | 5 |
| Seychelles | 30 | 10 |
| Sierra Leone | 70 | 10 |
| Slovakia | 10 / 40 | 10 |
| Slovenia | 10 / 50 / 60 | 5 |
| Solomon Islands | N/A | 5 |
| Somalia | 80 | 10 |
| South Sudan | N/A | 5 |
| Sri Lanka | 30 | 5 |
| Sudan | 30 | 5 |
| Suriname | 40 | 5 |
| Swaziland | 20 / 40 | 5 |
| Switzerland | 5 / 20 / 40 / 70 | 5 |
| Syria | 40 | 5 |
| Taiwan | 5 / 20 | 5 |
| Tajikistan | 30 | 5 |
| Tanzania | 30 | 5 |
| Thailand | 5 | 5 |
| Timor-Leste | N/A | 10 |
| Togo | 60 | 5 |
| Tonga | 60 | 5 |
| Trinidad and Tobago | 30 / 150 | 5 |
| Tunisia | 40 / 70 | 5 |
| Turkey | 10 / 30 | 5 |
| Turkmenistan | 40 | 10 |
| Turks and Caicos Islands | 40 / 150 | 5 |
| Uganda | 30 | 5 |
| Ukraine | 20 / 30 | 10 |
| United States (Alaska) | 2 / 5 / 40 | 1 |
| Uruguay | 20 / 40 | 10 |
| Uzbekistan | 20 | 10 |
| Vanuatu | N/A | 20 |
| Vatican City | 5 | N/A |
| Venezuela | 5 / 10 / 30 | 10 |
| Vietnam | 10 / 20 | 5 |
| Virgin Islands (U.S.) | 5 / 230 | 5 |
| Virgin Islands (British) | 40 / 150 | 5 |
| Yemen | 30 | 5 |
| Zambia | 20 / 40 | 5 |
| Zimbabwe | 20 / 60 / 80 | 5 |
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