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Recommendations and Best Practices for Maintaining a Positive Caller Reputation

Maintaining consumer trust in the voice communication channel is critical. Consumers expect to receive wanted and personalized communications, while being protected from spam and unwanted calls. This guide provides updated best practices for maintaining a positive caller reputation.

Why does caller reputation matter?

Throughout the industry, there are continued and increasing efforts to reduce unwanted calls to consumers. These efforts can often lead to calls being screened or blocked. This can make it difficult for your legitimate business calls to reach customers and get answered. Twilio has compiled a list of recommendations and best practices to maintain a positive caller reputation, minimize being blocked or flagged as spam, and improve answer rates.

Trust Hub

Twilio provides Trust Hub as a resource to engage with our customers to build trust within the telephony ecosystem. By registering in Trust Hub, our customers are able to experience increased voice call deliverability rates and higher call answer rates. Trust Hub allows customers to register their business profile, including Know Your Customer (KYC) information.

  • SHAKEN/STIR: Increase trust in your calls by displaying a trust indicator like "Caller Verified” on the called party’s phone
  • Caller ID Name (CNAM): Display the name of your business on the called party’s phone using Caller ID Name (CNAM) service
  • Voice Integrity: Allows you to register your Twilio phone numbers via Trust Hub which will then register them with the analytic engines responsible for running spam labeling algorithms on Telecom operators like AT&T and T-Mobile.
  • Branded Calls: Calls received by your customers are branded with your company name and logo.

For full details, see our Trust Hub documentation.

Voice Insights

Twilio's Voice Insights tooling allows users to see the carriers or providers for the call, the last SIP response, which side hung up, Post-Dial Delay (PDD), and other helpful troubleshooting details.

Insights empowers you to be more proactive in analyzing your call traffic, and helps spot trends like carrier Connection Rates.

For more information please review Voice Insights documentation.

Telemarketing and Advertising Requirements

If you use Twilio Voice Services to place telemarketing or advertising voice calls, you will be required to:

  • Obtain the consumers prior consent, as required by applicable law or regulation
  • At the beginning of the call, clearly and conspicuously disclosing the purpose of the voice call and identify and accurately represent yourself, or your organization, as applicable;
  • It is advised to consult with your legal council for guidance with applicable laws and regulations related to telemarketing and advertising voice calls in your jurisdiction and your end users jurisdiction.

Positive Caller Reputation Basic Do’s and Don’ts

  • Comply with all "Do Not Call" lists (e.g. US Only), and other Telephone Consumer Protection Act (TCPA) Act 47 U.S.C. § 227 requirements (US Only).
  • Keep your calling list(s) up to date, and remove numbers that don’t connect. Utilizing the suite of voice tools such as: Voice Insights (Voice Insights), Call Resources (Call Resources), Dial Call Status (Dial Call Status) and others provides Call Summary records which include key tracking metrics such as: 1)a last SIP response code which can be used to help identify numbers that aren't in service; e.g. last SIP response of 404 indicates none of the carriers Twilio tried to send the call over believed the called number was a valid destination.
  • Unreasonable answer and completion rates in accordance with the Twilio Voice Services Policy are often associated with spam, so you don’t want to be calling unassigned or disconnected numbers regularly, and no random “wardialing”. Voice Insights Dashboard provides a view into call completion rates in the Connection Rate section.
  • Provide a number and/or contact information that called parties can use to report alleged violations.
  • Be aware and mindful of carrier practices related to intra exchange calls and legitimate code-prefixes for the destination phone number in the “from” number, aka "neighbor" calls, see Purchasing Local Phone Numbers for further information. This method is often used by spam callers. Network operator call screening algorithms are aggressively monitoring for this behavior.

Be consistent in your phone number usage

  • Avoid using the same telephone number for multiple purposes (i.e. marketing, surveys, and support callbacks). To help reduce the likelihood of your calls being categorized as spam, we recommend aligning the context and content of your calls over a specific phone number throughout the life of your campaign. Phone numbers that have been reassigned for other purposes should wait at least 45 days before being reintroduced in a new campaign.

Be consistent in your outbound call volume

  • If your use case allows it, attempt to maintain a regular traffic volume, without unusual spiking.
  • Gradually ramp-up new campaign call volume incrementally over time, and avoid going from zero to full volume in a short period of time..
  • Calls for legitimate business purposes should not be too frequent, or outside of common working hours. What is deemed too frequent varies by use case. For example, the Fair Debt Collection Practices Act notes that 8 calls to a recipient phone number within seven consecutive days is considered to be harassment and the caller can be fined. For some products/services customers can specify how many times they want to be contacted and their preferred contact channels.

US ONLY: If you are following all best practices and still being labeled as spam, your best recourse will be to add your numbers to Here, you can register your phone numbers for legitimate calls to the major US cellular providers. Please note, this process can take a few weeks to complete.


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