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  • FAQ — Number Lookup API

    1. Does Plivo have an API to get information about phone numbers?

    Yes, with Plivo’s Lookup API you can find the proper local and E.164 phone number formatting, carrier information, and a caller ID names. For details, including usage examples, see Getting started with the Plivo Lookup API below.

    See our getting started guide for Plivo phone numbers for API resources on Plivo phone numbers.

    2. Getting started with the Plivo Lookup API

    Plivo’s Lookup API lets developers query phone number information, including number validation and formatting, carrier information, and portability information associated with a phone number. This guide answers some common questions:

    How can I submit a Lookup API request?

    To look up a phone number, your application needs to make an HTTP GET request to Plivo’s Lookup API resource with the phone number you wish to look up. Here's a simple cURL script example:

    curl -i --user auth_id_ID:auth_token \
    https://api.plivo.com/v1/LookupNumber/{number}?info=serviceprovider

    If you were to look up the phone number (204) 999-9999, for example, the Lookup API would return a response like:

    {
    	"api_id": "ac073f08-xxxx-xxxx-xxxx-c19435b84cd7",
    	"country": {
    		"name": "Canada",
    		"code_iso2": "CA",
    		"code_iso3": "CAN"
    	},
    	"number_format": {
    		"e164": "+12049999999",
    		"national": "(204) 999-9999",
    		"international": "+1 204-999-9999",
    		"rfc3966": "tel:+1-204-999-9999"
    	},
    	"service_provider": {
    		"mobile_country_code": "XXX",
    		"mobile_network_code": "XXX",
    		"name": "Carrier Name",
    		"type": "Number_type",
    		"ported": "true_or_false"
    	}
    }

    The Lookup API will return an HTTP 404 status with a response that contains "code": 20404 when a phone number is determined invalid. See the section below on how Plivo determines phone number validity.

    Where does Lookup data come from?

    Lookup utilizes a variety of authoritative sources to return the most accurate response for a given Lookup type.

    Lookup Type

    Data Sources

    Update Frequency

    Number validation and formatting

    International numbering plan data

    Real-time

    Carrier

    Mobile number portability and numbering plan data from each country’s phone number regulator (where available)

    Varies by country —
    minimum every 30 minutes, maximum every 24 hours

    Portability
    (US and CA)

    Information on whether the number is ported

    Minimum of every 24 hours

    Portability (international)

    TBD

    TBD

     

    How does Plivo determine phone number validity?

    Phone number validity is based on international phone numbering plan data administered by the ITU. Though the ITU should in theory have all global numbering plans on file, in practice, not every country files its numbering plans with the ITU. Additionally, some government authorities may let telecom companies be responsible for administrating numbering plans. As a result of this lack of centralization, maintaining an accurate global numbering plan is a patchwork process. Plivo works with carrier partners to maintain accurate global numbering plan data, but discrepancies can arise as numbering plans change and downstream providers must propagate these changes.

    Lookup will return an HTTP 404 status code if a phone number resource is invalid.

    What are the Carrier Lookup type values?

    In the response for a Carrier Lookup, the type property specifies whether the phone is a landline, mobile, or VoIP phone.

    • Landline (also called fixed or wireline) and mobile (or non-fixed or wireless) are service type designations provided by the carrier that owns the number.
    • VoIP is a classification of the carrier.

    VoIP phone numbers are easier to obtain, so they're sometimes used for fraudulent purposes. Customers often use Lookup to screen these numbers in their applications.

    Are there geographic support limitations?

    While the Lookup API is supported internationally, there are limitations to some request types:

    Phone number validation and formatting: Number validation and formatting lookups are supported in all countries worldwide.

    Carrier Lookup: This is supported worldwide with the following caveats:

    Can I process simultaneous Lookup API requests?

    The Lookup API handles only one phone number per request. For more information and recommendations, see Sending multiple requests to the Plivo Lookup API.

    Does Lookup cache response values?

    Lookup does not cache any response values.

    3. Sending multiple requests to the Plivo Lookup API

    5. What numbers can I get Lookup API details for?

    You can request information for any number — mobile, landline, VoIP, premium, or special.

     

    6. How are Lookup API requests billed?

    Every successful request is charged at $0.0040 per request. If your request is rejected or the callback returns with a 404 status, you will not be billed.

     

  • List of characters replaced by automatic encoding feature
     
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  • What is automatic encoding?

    Sometimes a Unicode character such as a smart quote, an em dash (—), or Unicode white space slips into your carefully crafted 125-character message, and your message gets segmented and priced at two messages instead of one.

    When Unicode characters are used in an SMS message, they must be encoded using the UCS-2 character set. UCS-2 characters take 16 bits to encode instead of the seven bits used by the GSM character set used for most common letters and symbols, so when a message includes any Unicode character, it's segmented at 70 characters instead of 160 characters per message segment.

    Plivo's intelligent message encoding feature detects easy-to-miss Unicode characters and replaces them with similar GSM-encoded characters to ensure that your message gets segmented at 160 characters and save you from sending two messages.

    Messages that include emoji or language-based characters such as kanji are not transliterated with automatic encoding. Here's the list of Unicode character sets replaced by automatic encoding.

  • Toll-Free Surcharge on Verizon, AT&T, and T-Mobile

    On September 1, 2020, Verizon began imposing a surcharge of $0.0025 for every outbound SMS message segment on its toll-free phone numbers. We pass this fee through to you with no additional upcharge, and the fee appears as a separate line item on invoices.

    Starting July 1, 2021, both T-Mobile and AT&T are also applying carrier passthrough fees for traffic terminating on toll-free numbers, on both SMS and MMS messages:

    AT&T SMS Outbound: $0.0025/message
    AT&T MMS Outbound: $0.003/message
    T-Mobile SMS Outbound/Inbound: $0.0025/message
    T-Mobile MMS Outbound/Inbound: $0.01/message

    Please contact our support team if you have additional questions.

  • Can the source number for an outbound text message be a non-Plivo number?

    No, you can only set your Plivo number as the source number for messages going to the US and Canada due to telecom regulations. You can, however, make an outbound voice call using Plivo’s APIs with a non-Plivo caller ID.

    Dynamic sender IDs (i.e. non-Plivo numbers) may be used as the source number for messages directed to international destinations. We cannot guarantee that the source number displayed to the message recipient will match the number that was originally used. 

  • Why should I authorize Plivo to view my SMS content?

    Authorizing Plivo to view your SMS content helps our customer success teams debug content-related delivery issues for your account. 

    Messages can be marked as spam by network carriers for many reasons. Content policy violations are among the most common reasons why a carrier will flag your message. Plivo’s customer success team can help avoid having messages marked as spam by:

    1. Suggesting changes to your SMS content to abide by regional content policies. 
    2. Helping you find a better-suited SMS product for your SMS traffic (long code, short code, toll-free, etc.)
    3. Raising issues with our downstream carriers to fix unexpected delivery failures.

    You can withdraw your consent at any time by visiting your Plivo console and reviewing your SMS settings.

    Note: Outbound and inbound SMS messages for which log redaction has been requested are not visible to customer success teams regardless of this preference.

  • Can I reply to customers who have opted out?

    Mobile subscribers who reply with a "STOP" message to your Plivo number are considered opted out. Any subsequent SMS messages to these phone numbers are blocked by Plivo. If you attempt to send messages to an opted-out customer, these messages will be marked failed with error code 200. 

    However, you may acknowledge the receipt of a "STOP" keywords from a customer to let them know that they've been opted out. Plivo allows you to send outbound messages to opted-out customers with the following conditions: 

    • The acknowledgment SMS message should be sent within five minutes of receipt of the "STOP" keyword from the subscriber.
    • At most, one SMS message is allowed to be sent to opted-out customers.  

     

  • What happens to my outbound messages if I don't have a sufficient balance in my Plivo account?

    Outbound messages will be labeled as "failed" with Plivo error code 900 and will not be forwarded to downstream carriers. For the next two minutes after we generate this error code, all send message API requests will fail with the error "Insufficient Credit." This is to let you take action before queuing more messages.

    All messages that are already queued in Plivo's system will continue to be marked "failed" with error code 900 as and when they are dequeued for processing until you add the necessary credits to the account.

  • Why were we charged for an undelivered SMS message? Why were we charged for a message that never reached the destination number?

    Plivo is a pay-as-you-go API platform. Plivo relies on its carrier network to deliver messages successfully. In some cases, messages may be sent by Plivo but not received by users. Plivo charges for messages that are successfully sent from the Plivo platform. 

    Do I get charged for inbound messages when the message_url or message_method is not specified?

    Yes. Inbound messages are free for long codes but are chargeable on toll-free and short code numbers, even without the message_url or message_method configured, when the inbound message state is set as received.

  • Can I send bulk SMS?

    Yes, you can send bulk SMS messages using a single Messaging API request. The request is similar to sending a single outbound SMS message, but you specify multiple dst (destination) numbers in E.164 format, separating the numbers with the "<" character — for example, "14156667777<14157778888<14158889999".

    See our SMS getting started guide and Bulk Messaging reference guide for details.

  • How can I receive SMS messages on my Plivo numbers?

    Prerequisites

    1. Sign up for a free Plivo trial account or log in to your Plivo account. 
    2. Check out our Server SDKs page for information on how to install the SDK for the programming language you want to use.
    3. Buy a Plivo phone number. You must have a phone number to receive and reply to SMS text messages. You can buy a Plivo phone number in available countries by visiting Phone Numbers > Buy Numbers. Check the SMS API coverage page for supported countries.
    4. Use a web hosting service to host your web application. Many inexpensive cloud hosting providers cost just a few dollars a month. Follow the instructions of your hosting provider to host your web application.

    Set up a web server

    For this example, let’s assume your web server is located at http://example.com. The following snippet will set up a route on your web server. Now, when we send an HTTP request to http://example.com/receive_sms, this route will be triggered.

    Create an application

    1. Create an application by either visiting Voice > XML and clicking on Add New Application, or by using Plivo’s Application API.
    2. Give your application a name. For this example, let’s call it Receive SMS. Enter your server URL (for example http://example.com/receive_sms) in the message URL field and set the method to POST. See our Application API reference guide to learn how to modify your application through our APIs.
    3. Click on Create Application to save your application.

    app.png

    Assign a Plivo number to your app

    1. Navigate to the Phone Numbers page and select the phone number you want to use for this app.
    2. Select Receive SMS (the name of the app) from the Plivo App drop-down list.
    3. Click on Update Number to save.

    num.png

    If you don’t have a number, go to Phone Numbers > Buy Numbers to purchase a Plivo phone number.

    buy.png

    Test it

    Send an SMS to your Plivo number using a regular mobile phone. Plivo will send a request to your Message URL.

  • How is an incoming message delivered to my application?

    An inbound message has two distinct stages: received and delivered or undelivered.

    1. Received

    Plivo receives an inbound message from a carrier. The user is charged for the inbound message. If the message_url or message_method is not configured in the user's application to the number that receives the message, the message remains marked as "received."

    2. Delivered/Undelivered

    Once Plivo receives a message, it sends a callback to the message_url. Based on the response Plivo gets, the message gets recategorized as either delivered or undelivered.

    • Delivered: The message_url is valid and active. After sending a callback to the message_url, the state of the message is set to "delivered."
    • Undelivered: The message_url is invalid, inactive, or not responding. Plivo will retry callbacks for the next 24 hours. If all callbacks fail, the status of the message will be set to "undelivered."
  • How does SMS concatenation work?

    When you send a long message that contains more than one SMS unit, the message is split into multiple units. Message concatenation assembles the multiple units back into a single message at the receiving end.

    Plivo’s Messaging API automatically breaks long SMS text messages into multiple SMS messages and adds a concatenation header to each message so that all can be stitched together (concatenated) on the recipient’s mobile device. See our documentation for complete details.

    Note: While Plivo’s APIs support concatenation, some carriers and handsets don't.

    How does Plivo charge for concatenated messages?

    SMS text messages that are longer than the SMS character limit are concatenated and billed separately as individual text messages.

    This screenshot shows a message that was divided into four units, with each unit costing USD 0.00250. The total cost to send this message was USD 0.01000.

    Screenshot.png

     

    How does Plivo handle delivery reports for concatenated SMS text messages?

    Delivery reports (DLR) for long messages are processed the same way as single-unit messages. Only one message delivery report and one DLR is generated for long messages.

  • What is the character limit for SMS text messages?

    Plivo’s APIs support sending SMS in all text-based languages, including English, French, Spanish, Chinese, Arabic, and more.

    Messages that contain only GSM03.38 seven-bit characters have a maximum limit of 1,600 characters. Messages that are longer than 160 characters will be split into multiple messages, with each message consisting of a maximum of 153 characters.

    Messages containing one or more UCS-2 16-bit Unicode characters have a maximum limit of 737 characters. Messages longer than 70 characters will be split into multiple messages, with each message consisting of a maximum of 67 characters. The list of Unicode characters can be found here: https://unicode-table.com/en/#control-character

    Multi-unit messages are automatically stitched back together and delivered as a single message in countries where mobile networks support long message concatenation.