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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 & Best Practices

If Twilio Voice Services are used to place telemarketing or advertising voice calls, the following industry best practices and rules governing telemarketing calls must be followed to reduce the risk of disciplinary action by Twilio, carriers, and/or third party analytic providers. 

If special circumstances justify deviation from these guidelines (such as a recruiting website with multiple positions, or a debt collector) document your practices on your website. 

1Compliance with TSR, TCPA, Truth-In-Caller ID (US calls only) 

a. Unless an exception applies,  calls covered by the TCPA must have consent from the call recipient.  The level of consent that the caller must obtain prior to placing a call depends on whether the call is classified as “informational” or “telemarketing”. 

  • For telemarketing calls, callers must obtain prior express written consent
  • For informational calls, callers are only required to obtain prior express consent. 

Because the TCPA is a strict liability statute, the sender of an autodialed call can be held liable for violating the TCPA, even if the sender had a reasonable, good-faith belief that it was calling a landline. 

b. Time Restrictions (TSR requirement).  Callers cannot place calls outside the hours of 8AM to 9PM, local time for the called party. Some states impose stricter requirements, including no calls on Sunday or on legal holidays and different hour restrictions. Bear in mind that the area code may not be indicative of the location of the called party (e.g, someone with a Los Angeles (213) area code may have moved to New York)

c. Repeated Calls.  Telemarketers cannot engage in fraudulent or abusive behavior, including causing any telephone to ring, or engaging any person in telephone conversation, repeatedly or continuously with intent to annoy, abuse, or harass any person at the called number. Example: “Limit calls to a given number to 2 in a single day and no more than 5 in a month”

d. Call Content.  Additional disclosures may apply where a caller will accept a sales order or charitable contribution over the phone, or is marketing certain types of regulated products or services.  Additionally, the TSR restricts calls with abusive or fraudulent content.  

e. Reassigned Numbers Database. Called numbers should be checked against the Reassigned Numbers Database  on a regular scheduled cadence (using date of consent or last verified Established Business Relationship (EBR))


2. Best Practices When Placing a Call

a. When calling a given number repeatedly, use the same caller-ID for each call. 

b. Associate a descriptive Caller ID Name (CNAM) with your caller-ID(s) (e.g. Phone Numbers). See Brand Your Calls Using CNAM and Verifying Caller ID at Scale with Twilio for instructions.

c. Announce the name of the caller at the beginning of the message. The name must be clear and unambiguous regarding its affiliation to the caller.

d. Announce how consent was obtained.

  • Example: Hi this is Gloria with AAA Insurance, Salt Lake City, Utah. Conrad Doe came to the website last week and requested that we call with an auto insurance quote. Is Conrad available?

e. Allow at least 30 seconds (5 ring cycles) for the called party to answer. Ensure the called party hears audio within 2 seconds of the greeting. No silent calls.


3. Managing customer concerns when calls are answered 

a. Address any questions or concerns raised about the nature of the call before continuing. Be prepared to offer a web URL and telephone number where the called party can turn for more information.

b. If the called party indicates that they did not consent, or that they are no longer interested and wish to revoke consent indicate that you will not call again and remove them from your call list.

c. If the call is answered by voicemail, do not hang up. Leave a message with the elements in (1b) above, plus a call-back number. The call back number should answer 24×7 and include an opt-out mechanism.


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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