CPaaS can add text messaging, phone calls, in-app voice and video, chat and email to an application. Text messaging covers SMS, MMS, RCS and WhatsApp. On top of those channels, providers sell features such as call recording, phone menus and verification codes. Each channel suits a different job and has its own requirement before it works.
\n","summary":"CPaaS can add text messaging (SMS, MMS, RCS and WhatsApp), phone calls, in-app voice and video, chat and email to an application, plus features built on those channels such as call recording, phone menus and verification codes. Each channel suits a different job and has its own requirement before it works, such as carrier registration for US texting or a registered template to start a WhatsApp conversation.","publishedAt":"2026-07-29T16:58:52.045","verifiedAt":"2026-07-17T00:00:00","editorialStatus":"APPROVED","lastReviewedAt":"2026-10-10T02:57:26.276","nextReviewDueAt":"2026-10-17T00:00:00","templateVersion":"v2","aliases":["What channels does CPaaS support?","What can you build with communication APIs?","CPaaS features list","What communication APIs can I add to my app?","Which channels do CPaaS providers offer?","CPaaS capabilities explained","SMS, voice, video and chat APIs for applications","What does a communications platform as a service include?","CPaaS channel and feature comparison","Adding SMS, WhatsApp and voice to software","What features come with CPaaS platforms?","CPaaS API capabilities overview"],"confidenceScore":88,"confidenceLabel":"High","canonicalUrl":null},"contributor":{"id":"ec39deab-44fe-48d8-9029-fefe993ab85a","slug":"answer-stack","displayName":"AnswerStack","websiteUrl":null},"contributorOrganizationProfile":null,"contributorPerson":null,"sections":[{"id":"386ab115-4aa6-4a0b-b76f-0ed36b92b96f","sectionKey":"channels_table","sectionType":"table_section","heading":"The channels at a glance","introMarkdown":null,"introHtml":null,"outroMarkdown":null,"outroHtml":null,"contentJson":{"rows":[{"cells":["SMS and MMS","A short alert to a mobile number","A phone number, plus carrier registration for US 10-digit numbers"]},{"cells":["RCS","A branded message with reply buttons","A branded sender profile approved by carriers, and a recipient number that can receive RCS"]},{"cells":["WhatsApp","Notifications and two-way service for WhatsApp users","A WhatsApp Business Account and a registered template to start a conversation"]},{"cells":["Phone calls","A caller who needs to hear or key in something","A phone number and code that tells the provider how to handle the call"]},{"cells":["In-app voice, video and chat","A call or chat that starts from your website or app","The provider's client SDK in your app and tokens issued by your server"]},{"cells":["Email","Order confirmations and account notices","An endpoint for the provider's delivery and engagement events, if your application acts on them"]}],"columns":["Channel","A job it suits","What the application uses"]},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":10},{"id":"7c018912-1584-42c2-916e-b82d88f9a391","sectionKey":"text_messaging","sectionType":"markdown_section","heading":"Text messaging: SMS, MMS, RCS and WhatsApp","introMarkdown":"SMS reaches any phone with text service and asks the recipient to install nothing, so it suits order alerts and reminders. Twilio's [US price list](https://www.twilio.com/en-us/sms/pricing/us) charges $0.0083 per SMS segment and $0.022 for an outbound MMS. Carriers add per-message fees on top, such as $0.0035 for an outbound SMS to AT&T. Before a US 10-digit number can send application traffic, Twilio's [10DLC documentation](https://www.twilio.com/docs/messaging/compliance/a2p-10dlc) says the sender must register a brand and a campaign.\n\nAdding texting doesn't always mean building it. Atlantech's [atlantech|text](https://www.atlantech.net/solutions/voice/atlantech-text) puts SMS and MMS into Microsoft Teams, on the direct-dial number an employee already has, starting at $10 per number per month. Nobody writes code, because the channel is added to an app staff already use. CPaaS is the route when the texts have to come from software your team develops or extends. We explain that distinction in [what CPaaS is](https://www.answerstack.io/q/what-is-cpaas).\n\nRCS makes the text interactive. Twilio's [RCS documentation](https://www.twilio.com/docs/rcs) describes a branded sender profile in place of a phone number, up to 11 suggested replies, cards that can be sent together as a carousel, and delivery and read receipts.\n\nSuppose a furniture store texts a customer a delivery window. Over SMS, the customer has to type an answer. Over RCS, the message arrives under the store's name with buttons for confirming or rescheduling. The store also gets delivery and read receipts.\n\nRCS doesn't reach every customer. Twilio lists Android and iOS 18 devices as compatible. Its [RCS onboarding guide](https://www.twilio.com/docs/rcs/onboarding) adds that carriers must approve the sender and that not all phone numbers can receive RCS messages. Twilio's Messaging Services send by SMS or MMS when an RCS message fails or the carrier doesn't support it, so the store can still send those customers the delivery window by SMS.\n\nWhatsApp reaches people inside an app they already use. Twilio [sends WhatsApp messages](https://www.twilio.com/docs/whatsapp/api) through the same messaging API as SMS, with the address written as `whatsapp:` followed by the phone number. A customer's WhatsApp message arrives at the application's webhook in the same format as an incoming text. So a store that already handles SMS replies can reuse most of that code.\n\nThe rules differ from SMS in one way that shapes the design. WhatsApp requires a notification the business starts to use a template registered in advance. Free-form messages are allowed inside a customer service window, which lasts 24 hours after the customer's most recent message. So the furniture store's delivery notice goes out as a template. If the customer answers, the store can reply in its own words for the next 24 hours.","introHtml":"SMS reaches any phone with text service and asks the recipient to install nothing, so it suits order alerts and reminders. Twilio's US price list charges $0.0083 per SMS segment and $0.022 for an outbound MMS. Carriers add per-message fees on top, such as $0.0035 for an outbound SMS to AT&T. Before a US 10-digit number can send application traffic, Twilio's 10DLC documentation says the sender must register a brand and a campaign.
\nAdding texting doesn't always mean building it. Atlantech's atlantech|text puts SMS and MMS into Microsoft Teams, on the direct-dial number an employee already has, starting at $10 per number per month. Nobody writes code, because the channel is added to an app staff already use. CPaaS is the route when the texts have to come from software your team develops or extends. We explain that distinction in what CPaaS is.
\nRCS makes the text interactive. Twilio's RCS documentation describes a branded sender profile in place of a phone number, up to 11 suggested replies, cards that can be sent together as a carousel, and delivery and read receipts.
\nSuppose a furniture store texts a customer a delivery window. Over SMS, the customer has to type an answer. Over RCS, the message arrives under the store's name with buttons for confirming or rescheduling. The store also gets delivery and read receipts.
\nRCS doesn't reach every customer. Twilio lists Android and iOS 18 devices as compatible. Its RCS onboarding guide adds that carriers must approve the sender and that not all phone numbers can receive RCS messages. Twilio's Messaging Services send by SMS or MMS when an RCS message fails or the carrier doesn't support it, so the store can still send those customers the delivery window by SMS.
\nWhatsApp reaches people inside an app they already use. Twilio sends WhatsApp messages through the same messaging API as SMS, with the address written as whatsapp: followed by the phone number. A customer's WhatsApp message arrives at the application's webhook in the same format as an incoming text. So a store that already handles SMS replies can reuse most of that code.
The rules differ from SMS in one way that shapes the design. WhatsApp requires a notification the business starts to use a template registered in advance. Free-form messages are allowed inside a customer service window, which lasts 24 hours after the customer's most recent message. So the furniture store's delivery notice goes out as a template. If the customer answers, the store can reply in its own words for the next 24 hours.
\n","outroMarkdown":null,"outroHtml":null,"contentJson":{},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":20},{"id":"87a0b8db-ddc9-47d7-ba50-d17d4747df75","sectionKey":"phone_calls_and_call_control","sectionType":"markdown_section","heading":"Phone calls and call control","introMarkdown":"Phone calls come in two layers. The first is the call itself. Twilio's [voice API](https://www.twilio.com/docs/voice/api) places an outbound call with one request to its Calls resource. The second is control over what happens during the call, and that layer is what makes a call programmable.\n\nTwilio's [voice instructions](https://www.twilio.com/docs/voice/twiml) show what that control looks like. Its verbs include Say, Play, Dial and Record, and a call can prompt the caller for keypad input. So a caller to the furniture store could key in an order number. The store's application looks it up, and the call reads back the delivery date or dials the store. Your code makes each of those choices while the call is in progress, as we describe in [how CPaaS works](https://www.answerstack.io/q/how-does-cpaas-work).\n\nCalls are billed by the minute. Twilio's pay-as-you-go [US voice prices](https://www.twilio.com/en-us/voice/pricing/us) are $0.0085 per minute for an inbound call to a local number and $0.0140 per minute for an outbound local call. The local number rents for $1.15 a month.","introHtml":"Phone calls come in two layers. The first is the call itself. Twilio's voice API places an outbound call with one request to its Calls resource. The second is control over what happens during the call, and that layer is what makes a call programmable.
\nTwilio's voice instructions show what that control looks like. Its verbs include Say, Play, Dial and Record, and a call can prompt the caller for keypad input. So a caller to the furniture store could key in an order number. The store's application looks it up, and the call reads back the delivery date or dials the store. Your code makes each of those choices while the call is in progress, as we describe in how CPaaS works.
\nCalls are billed by the minute. Twilio's pay-as-you-go US voice prices are $0.0085 per minute for an inbound call to a local number and $0.0140 per minute for an outbound local call. The local number rents for $1.15 a month.
\n","outroMarkdown":null,"outroHtml":null,"contentJson":{},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":30},{"id":"1057ed0e-2d04-43e3-97bf-ce76fef7d4f6","sectionKey":"in_app_voice_video_chat","sectionType":"markdown_section","heading":"Voice, video and chat inside your own app","introMarkdown":"A conversation doesn't always need a phone number. Twilio has client-side SDKs for voice, video and conversations that run in a browser or phone app, each signed in with an [access token](https://www.twilio.com/docs/iam/access-tokens). The customer talks from your website or app without dialing a number, and the provider's infrastructure carries the call. Twilio's [voice price list](https://www.twilio.com/en-us/voice/pricing/us) charges $0.0040 per minute for the browser or app leg of a voice call.\n\nSuppose the furniture store's customer opens the store's website and starts a video call to show a damaged table leg. The store's developers build the call screen with the provider's SDK, and the store's server issues each user a short-lived token to sign in. We cover that in [how CPaaS APIs authenticate requests and report events](https://www.answerstack.io/q/what-are-cpaas-apis-and-how-do-they-connect-communications-to-an-application).","introHtml":"A conversation doesn't always need a phone number. Twilio has client-side SDKs for voice, video and conversations that run in a browser or phone app, each signed in with an access token. The customer talks from your website or app without dialing a number, and the provider's infrastructure carries the call. Twilio's voice price list charges $0.0040 per minute for the browser or app leg of a voice call.
\nSuppose the furniture store's customer opens the store's website and starts a video call to show a damaged table leg. The store's developers build the call screen with the provider's SDK, and the store's server issues each user a short-lived token to sign in. We cover that in how CPaaS APIs authenticate requests and report events.
\n","outroMarkdown":null,"outroHtml":null,"contentJson":{},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":40},{"id":"4839bf80-0409-492d-bb88-cf23967b34ea","sectionKey":"email_channel","sectionType":"markdown_section","heading":"Email","introMarkdown":"CPaaS email is for mail an application sends. For the furniture store, that means the order confirmation and the delivery-day notice.\n\nTwilio SendGrid posts event data to the application, and its [event reference](https://www.twilio.com/docs/sendgrid/for-developers/tracking-events/event) sorts those events into two groups. Delivery events describe the message's path to the receiving mail server. Processed means SendGrid accepted the message, and delivered means the receiving server accepted it. Deferred means the receiving server rejected it temporarily. Bounce means the receiving server doesn't accept mail sent to that recipient. Engagement events report what was recorded for the recipient, such as an open, a click, a spam report or an unsubscribe.\n\nThe two groups answer different questions, so the store's application should handle them differently. A bounce on the order confirmation tells the store that message was not accepted, so the delivery notice may need another channel the customer has agreed to. A delivered event says the receiving server accepted the message. Whether an open was recorded is a separate event. An unsubscribe is an instruction, so the application has to store it against the customer before the next send.","introHtml":"CPaaS email is for mail an application sends. For the furniture store, that means the order confirmation and the delivery-day notice.
\nTwilio SendGrid posts event data to the application, and its event reference sorts those events into two groups. Delivery events describe the message's path to the receiving mail server. Processed means SendGrid accepted the message, and delivered means the receiving server accepted it. Deferred means the receiving server rejected it temporarily. Bounce means the receiving server doesn't accept mail sent to that recipient. Engagement events report what was recorded for the recipient, such as an open, a click, a spam report or an unsubscribe.
\nThe two groups answer different questions, so the store's application should handle them differently. A bounce on the order confirmation tells the store that message was not accepted, so the delivery notice may need another channel the customer has agreed to. A delivered event says the receiving server accepted the message. Whether an open was recorded is a separate event. An unsubscribe is an instruction, so the application has to store it against the customer before the next send.
\n","outroMarkdown":null,"outroHtml":null,"contentJson":{},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":50},{"id":"9271f877-a133-4514-9c92-c0b2d739a9c2","sectionKey":"features_on_top","sectionType":"markdown_section","heading":"Features built on top of the channels","introMarkdown":"Some features belong to one channel. Call recording and phone menus are built from the Record instruction and keypad prompts described above. Other features use several channels, and verification is the common one. Twilio's [Verify](https://www.twilio.com/docs/verify) confirms a user through SMS, voice, email, WhatsApp, an authenticator code, push, passkeys or silent network authentication. A login flow can offer a code by text and fall back to a call or an email through the same API.","introHtml":"Some features belong to one channel. Call recording and phone menus are built from the Record instruction and keypad prompts described above. Other features use several channels, and verification is the common one. Twilio's Verify confirms a user through SMS, voice, email, WhatsApp, an authenticator code, push, passkeys or silent network authentication. A login flow can offer a code by text and fall back to a call or an email through the same API.
\n","outroMarkdown":null,"outroHtml":null,"contentJson":{},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":60},{"id":"370ad881-f697-4e0f-932f-799b8f07e41b","sectionKey":"changing_channel_list","sectionType":"markdown_section","heading":"Why the list keeps changing","introMarkdown":"A provider's list of channels is not fixed. Microsoft [announced on September 23, 2026](https://learn.microsoft.com/en-us/azure/communication-services/acs-retirement-and-breaking-changes-guide) that it is retiring Azure Communication Services as a standalone offering on September 30, 2028, and its SMS, email, chat and WhatsApp messaging services end on that date. A channel's reach changes too, as RCS shows.\n\nSo check the provider's current list before you design around a channel. It also helps to store each customer under your own ID, with the phone number, WhatsApp address and email address as attributes of that record. When a customer changes a number or a provider drops a channel, you update how you reach that customer, and the history stays attached to the same record.","introHtml":"A provider's list of channels is not fixed. Microsoft announced on September 23, 2026 that it is retiring Azure Communication Services as a standalone offering on September 30, 2028, and its SMS, email, chat and WhatsApp messaging services end on that date. A channel's reach changes too, as RCS shows.
\nSo check the provider's current list before you design around a channel. It also helps to store each customer under your own ID, with the phone number, WhatsApp address and email address as attributes of that record. When a customer changes a number or a provider drops a channel, you update how you reach that customer, and the history stays attached to the same record.
\n","outroMarkdown":null,"outroHtml":null,"contentJson":{},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":70}],"citations":[{"title":"Services available in Azure Communication Services","url":"https://learn.microsoft.com/en-us/azure/communication-services/concepts/services","excerpt":"Voice and video calling - Embed voice and video calls into websites and native applications. Phone calling - Add telephony and Public Switched Telephone Network (PSTN) access to your application.","quoteText":null,"sourceRole":"PRIMARY","verifiedAt":"2026-07-17T00:00:00","supportsText":"Full CPaaS capability inventory: identity, chat, email, SMS, WhatsApp, voice and video calling, PSTN phone calling, call automation, Teams interoperability, job router, AI","domain":"learn.microsoft.com","publisherName":"Microsoft Learn"},{"title":"A2P 10DLC messaging compliance","url":"https://www.twilio.com/docs/messaging/compliance/a2p-10dlc","excerpt":"A2P (Application-to-Person) 10DLC (10-digit long code) is the standard that United States telecom carriers have put in place to ensure that SMS traffic to US end users through long code phone numbers is verified and consensual.","quoteText":null,"sourceRole":"PRIMARY","verifiedAt":"2026-07-17T00:00:00","supportsText":"US 10DLC registration requirement, brand and campaign layers, carrier fees for unregistered traffic, lower filtering and higher throughput when registered, Low-Volume Mixed campaign cap, toll-free and short codes outside the 10DLC system","domain":"twilio.com","publisherName":"Twilio Docs"},{"title":"RCS Business Messaging","url":"https://www.twilio.com/docs/rcs","excerpt":"Add message features such as suggested replies, call-to-action (CTA) buttons, dynamic carousels, and location sharing.","quoteText":null,"sourceRole":"PRIMARY","verifiedAt":"2026-07-17T00:00:00","supportsText":"RCS features: suggested replies, call-to-action buttons, dynamic carousels, location sharing, delivery and read receipts, branded sender profile, Android and iOS 18 support","domain":"twilio.com","publisherName":"Twilio Docs"},{"title":"Overview of Advanced Messaging for WhatsApp","url":"https://learn.microsoft.com/en-us/azure/communication-services/concepts/advanced-messaging/whatsapp/whatsapp-overview","excerpt":"Support for business-initiated and customer-initiated conversations. Initiate conversations with WhatsApp users using templates.","quoteText":null,"sourceRole":"PRIMARY","verifiedAt":"2026-07-17T00:00:00","supportsText":"Business-initiated vs customer-initiated WhatsApp conversations, template requirement, delivery and read reports, WhatsApp usernames and business-scoped user IDs in 2026, empty from/to fields breaking change","domain":"learn.microsoft.com","publisherName":"Microsoft Learn"},{"title":"Programmable Voice","url":"https://www.twilio.com/docs/voice","excerpt":"Quickly make and receive voice calls in your application... respond to incoming phone calls, gather user input, record calls.","quoteText":null,"sourceRole":"PRIMARY","verifiedAt":"2026-07-17T00:00:00","supportsText":"Outbound and inbound calls from an application, gathering keypad input, call recording, converting live or recorded audio into searchable text","domain":"twilio.com","publisherName":"Twilio Docs"},{"title":"ConversationRelay","url":"https://www.twilio.com/docs/voice/twiml/connect/conversationrelay","excerpt":"handles the complexities of live, synchronous voice calls, such as speech-to-text (STT) and text-to-speech (TTS) conversions, session management, and low-latency communication.","quoteText":null,"sourceRole":"PRIMARY","verifiedAt":"2026-07-17T00:00:00","supportsText":"Speech-to-text and text-to-speech handling, session management, low-latency WebSocket connection to an AI application, interruption controls and sensitivity settings","domain":"twilio.com","publisherName":"Twilio Docs"},{"title":"AI in Azure Communication Services","url":"https://learn.microsoft.com/en-us/azure/communication-services/concepts/ai","excerpt":"AI applications use Azure's service-to-service WebSockets API to stream audio data. This works in both directions, your AI can listen to a call, and speak.","quoteText":null,"sourceRole":"PRIMARY","verifiedAt":"2026-07-17T00:00:00","supportsText":"Direct integrations vs accessors, speech synthesis and recognition for voice bots, closed captions, background effects, noise suppression, raw media access, bidirectional audio streaming, real-time transcription, call recording, Azure Bot Service chat integration","domain":"learn.microsoft.com","publisherName":"Microsoft Learn"},{"title":"RFC 8825: Overview: Real-Time Protocols for Browser-Based Applications","url":"https://www.rfc-editor.org/rfc/rfc8825","excerpt":"This document gives an overview and context of a protocol suite intended for use with real-time applications that can be deployed in browsers.","quoteText":null,"sourceRole":"PRIMARY","verifiedAt":"2026-07-17T00:00:00","supportsText":"WebRTC as the standardized protocol suite behind browser-based embedded voice and video calling","domain":"rfc-editor.org","publisherName":"IETF / RFC Editor"},{"title":"Overview of Azure Communication Services email","url":"https://learn.microsoft.com/en-us/azure/communication-services/concepts/email/email-overview","excerpt":"Sender authentication support: The platform enables support for Sender Policy Framework (SPF) and Domain Keys Identified Mail (DKIM) settings for both Azure-managed and custom domains.","quoteText":null,"sourceRole":"PRIMARY","verifiedAt":"2026-07-17T00:00:00","supportsText":"High-volume transactional, bulk and marketing email for A2P use cases, SDK and SMTP access, custom verified domains, SPF and DKIM support, near real-time delivery status, suppression list opt-out handling, bounce/blocked/open/click engagement tracking","domain":"learn.microsoft.com","publisherName":"Microsoft Learn"},{"title":"Email sender guidelines","url":"https://support.google.com/a/answer/81126","excerpt":"If you send more than 5,000 messages per day to Gmail accounts, follow the Requirements for sending 5,000 or more messages per day. Keep spam rates reported in Postmaster Tools below 0.30%.","quoteText":null,"sourceRole":"PRIMARY","verifiedAt":"2026-07-17T00:00:00","supportsText":"Requirements for senders of more than 5,000 messages per day to Gmail: SPF, DKIM, DMARC at policy none, valid forward and reverse DNS, From header alignment, one-click unsubscribe, spam rate below 0.30 percent","domain":"support.google.com","publisherName":"Google Workspace Admin Help"},{"title":"Verify","url":"https://www.twilio.com/docs/verify","excerpt":"Quickly verify users via SMS, Passkeys, Silent Network Auth, Voice, WhatsApp, TOTP, Push, Silent Device Approval, and Email.","quoteText":null,"sourceRole":"PRIMARY","verifiedAt":"2026-07-17T00:00:00","supportsText":"Verification channels available through a CPaaS: SMS, passkeys, silent network auth, voice, WhatsApp, TOTP, push, silent device approval, email","domain":"twilio.com","publisherName":"Twilio Docs"},{"title":"Lookup","url":"https://www.twilio.com/docs/lookup","excerpt":"Line Type Intelligence: Filter out invalid numbers and landline numbers before sending messages. SIM Swap: identify potential fraud by identifying SIM swaps.","quoteText":null,"sourceRole":"PRIMARY","verifiedAt":"2026-07-17T00:00:00","supportsText":"Phone number intelligence packages: line type intelligence, reassigned number, identity match, caller name, SIM swap, call forwarding, SMS pumping risk score, line status","domain":"twilio.com","publisherName":"Twilio Docs"},{"title":"Number Verification API","url":"https://camaraproject.org/number-verification/","excerpt":"Network operator knows to which subscriber a network-connected mobile phone belongs and what its associated phone number is.","quoteText":null,"sourceRole":"PRIMARY","verifiedAt":"2026-07-17T00:00:00","supportsText":"Network-based number verification: operator knowledge of subscriber-to-number mapping and SIM identification, removing the manual SMS code step in signup, login and transaction validation","domain":"camaraproject.org","publisherName":"CAMARA Project"},{"title":"47 CFR 64.1200 - Delivery restrictions","url":"https://www.law.cornell.edu/cfr/text/47/64.1200","excerpt":"honored within a reasonable time not to exceed ten business days from receipt of such request","quoteText":null,"sourceRole":"PRIMARY","verifiedAt":"2026-07-17T00:00:00","supportsText":"Revocation of prior express consent must be honored within a reasonable time not to exceed ten business days; reply keywords stop, quit, end, revoke, opt out, cancel and unsubscribe are reasonable methods","domain":"law.cornell.edu","publisherName":"Legal Information Institute, Cornell Law School"},{"title":"Order, CG Docket No. 02-278 (DA 26-12), adopted January 6, 2026","url":"https://docs.fcc.gov/public/attachments/DA-26-12A1.pdf","excerpt":"we find that good cause exists to extend the effective date for this requirement until January 31, 2027","quoteText":null,"sourceRole":"PRIMARY","verifiedAt":"2026-07-17T00:00:00","supportsText":"FCC extended the waiver of the cross-subject-matter portion of 47 CFR 64.1200(a)(10) until January 31, 2027; order adopted and released January 6, 2026","domain":"docs.fcc.gov","publisherName":"Federal Communications Commission, Consumer and Governmental Affairs Bureau"}],"revisions":[{"revisedAt":"2026-07-20T16:58:52.045+00:00","versionLabel":"Originally published","note":"","reviewedBy":null}],"relatedAnswers":[{"id":"4aead8ad-6924-4536-85c7-da4330db063e","slug":"what-is-cpaas","question":"What is CPaaS?","publishedAt":"2026-09-15T16:58:42.641","confidenceScore":92,"confidenceLabel":"High","industry":{"id":"ff619d7c-d7d7-485e-a05a-53fba07f33ed","slug":"telecommunications","label":"Telecommunications","description":"Business voice, fiber, UCaaS, and network services"},"topic":{"slug":"cpaas","label":"CPaaS","description":"Communications platform as a service: APIs for adding voice, SMS, and video to applications.","schemaKind":null},"contributor":{"id":"ec39deab-44fe-48d8-9029-fefe993ab85a","slug":"answer-stack","displayName":"AnswerStack","websiteUrl":null},"snippet":"CPaaS, communications platform as a service, is a cloud service that sells communication capabilities as APIs. Developers use them to put texting, calling, video or email inside software their company already runs. It sells programmable building blocks, billed mostly by usage, and your team assembles them into the product. The alternatives are a finished service or software that already has messaging built in.","url":"/q/what-is-cpaas"},{"id":"774fb173-41db-4d7a-9929-e21132cf8bc9","slug":"what-are-cpaas-apis-and-how-do-they-connect-communications-to-an-application","question":"What are CPaaS APIs, and how do they connect communications to an application?","publishedAt":"2026-09-11T16:58:49.552","confidenceScore":91,"confidenceLabel":"High","industry":{"id":"ff619d7c-d7d7-485e-a05a-53fba07f33ed","slug":"telecommunications","label":"Telecommunications","description":"Business voice, fiber, UCaaS, and network services"},"topic":{"slug":"cpaas","label":"CPaaS","description":"Communications platform as a service: APIs for adding voice, SMS, and video to applications.","schemaKind":null},"contributor":{"id":"ec39deab-44fe-48d8-9029-fefe993ab85a","slug":"answer-stack","displayName":"AnswerStack","websiteUrl":null},"snippet":"CPaaS APIs turn messages, calls and phone numbers into objects your code can create, look up and change. Your application sends authenticated HTTPS requests to create them and hosts URLs where the provider posts status updates and inbound traffic. The provider's ID for each message or call, stored beside your own record, is what links a later event to the order or customer it belongs to.","url":"/q/what-are-cpaas-apis-and-how-do-they-connect-communications-to-an-application"},{"id":"10efb537-bcac-4f04-b26b-c834ce7a32ad","slug":"how-does-cpaas-work","question":"How does CPaaS work?","publishedAt":"2026-08-07T16:58:44.951","confidenceScore":92,"confidenceLabel":"High","industry":{"id":"ff619d7c-d7d7-485e-a05a-53fba07f33ed","slug":"telecommunications","label":"Telecommunications","description":"Business voice, fiber, UCaaS, and network services"},"topic":{"slug":"cpaas","label":"CPaaS","description":"Communications platform as a service: APIs for adding voice, SMS, and video to applications.","schemaKind":null},"contributor":{"id":"ec39deab-44fe-48d8-9029-fefe993ab85a","slug":"answer-stack","displayName":"AnswerStack","websiteUrl":null},"snippet":"CPaaS puts communication channels, such as calling and texting, behind an API. For voice and SMS, the provider holds the phone numbers and carrier connections. Your application sends an authenticated HTTPS request to send a text or place a call, and the provider hands it to the carrier network. For incoming traffic, providers commonly send a request to a URL you host and follow the instructions your code returns. The main charges are per message or per minute, and US texting from 10-digit numbers needs registration first.","url":"/q/how-does-cpaas-work"}],"contributorStats":{"verifiedAnswers":149,"openDisputes":0},"schemaJson":{"@context":"https://schema.org","@type":"Question","name":"Which communication channels and features can CPaaS add to an application?","text":"Which communication channels and features can CPaaS add to an application?","url":"https://www.answerstack.io/q/which-communication-channels-and-features-can-cpaas-add-to-an-application","answerCount":1,"datePublished":"2026-07-29T16:58:52.045","about":[{"@type":"Thing","name":"CPaaS"},{"@type":"Thing","name":"Telecommunications"}],"acceptedAnswer":{"@type":"Answer","text":"CPaaS can add text messaging, phone calls, in-app voice and video, chat and email to an application. Text messaging covers SMS, MMS, RCS and WhatsApp. On top of those channels, providers sell features such as call recording, phone menus and verification codes. Each channel suits a different job and has its own requirement before it works.","url":"https://www.answerstack.io/q/which-communication-channels-and-features-can-cpaas-add-to-an-application","upvoteCount":0,"datePublished":"2026-07-29T16:58:52.045","dateModified":"2026-07-17T00:00:00","citation":[{"@type":"CreativeWork","name":"Services available in Azure Communication Services","url":"https://learn.microsoft.com/en-us/azure/communication-services/concepts/services"},{"@type":"CreativeWork","name":"A2P 10DLC messaging compliance","url":"https://www.twilio.com/docs/messaging/compliance/a2p-10dlc"},{"@type":"CreativeWork","name":"RCS Business Messaging","url":"https://www.twilio.com/docs/rcs"},{"@type":"CreativeWork","name":"Overview of Advanced Messaging for WhatsApp","url":"https://learn.microsoft.com/en-us/azure/communication-services/concepts/advanced-messaging/whatsapp/whatsapp-overview"},{"@type":"CreativeWork","name":"Programmable Voice","url":"https://www.twilio.com/docs/voice"},{"@type":"CreativeWork","name":"ConversationRelay","url":"https://www.twilio.com/docs/voice/twiml/connect/conversationrelay"},{"@type":"CreativeWork","name":"AI in Azure Communication Services","url":"https://learn.microsoft.com/en-us/azure/communication-services/concepts/ai"},{"@type":"CreativeWork","name":"RFC 8825: Overview: Real-Time Protocols for Browser-Based Applications","url":"https://www.rfc-editor.org/rfc/rfc8825"},{"@type":"CreativeWork","name":"Overview of Azure Communication Services email","url":"https://learn.microsoft.com/en-us/azure/communication-services/concepts/email/email-overview"},{"@type":"CreativeWork","name":"Email sender guidelines","url":"https://support.google.com/a/answer/81126"},{"@type":"CreativeWork","name":"Verify","url":"https://www.twilio.com/docs/verify"},{"@type":"CreativeWork","name":"Lookup","url":"https://www.twilio.com/docs/lookup"},{"@type":"CreativeWork","name":"Number Verification API","url":"https://camaraproject.org/number-verification/"},{"@type":"CreativeWork","name":"47 CFR 64.1200 - Delivery restrictions","url":"https://www.law.cornell.edu/cfr/text/47/64.1200"},{"@type":"CreativeWork","name":"Order, CG Docket No. 02-278 (DA 26-12), adopted January 6, 2026","url":"https://docs.fcc.gov/public/attachments/DA-26-12A1.pdf"}]}}}