Communications & messaging terminology, explained

Application-to-Person (A2P) messaging is the process of sending messages from a software application to a mobile user. Unlike person-to-person (P2P) texts, A2P messages are generated programmatically — for example, OTP codes, appointment reminders, shipping notifications, and marketing campaigns. A2P traffic is the dominant revenue stream for most CPaaS providers and is subject to carrier-specific regulations and filtering.

A messaging aggregator is an intermediary that connects businesses to multiple mobile network operators (MNOs) through a single integration point. Aggregators consolidate message routing across carriers and geographies, handling delivery optimization, failover, and compliance. Bind operates as both a direct carrier connection and an aggregator, offering businesses simplified global reach without managing individual operator relationships.

An API is a set of rules and protocols that enables different software systems to communicate with each other. In the messaging context, APIs allow businesses to programmatically send and receive messages, query number intelligence data, and trigger authentication flows — all without building the underlying telecom infrastructure themselves.

Two-factor authentication (2FA) and multi-factor authentication (MFA) add extra layers of identity verification beyond a password. In messaging, this typically involves sending a one-time password (OTP) via SMS, RCS, or voice to confirm a user's identity. 2FA is one of the most common A2P use cases globally, protecting login flows, financial transactions, and account recovery processes.

Bulk messaging refers to sending large volumes of messages — often thousands or millions — to multiple recipients simultaneously. Used for marketing campaigns, alerts, and notifications, bulk messaging requires careful management of throughput, delivery rates, and regulatory compliance to avoid carrier filtering or blacklisting.

Business messaging encompasses all forms of messaging initiated by or on behalf of an enterprise to communicate with customers. This includes transactional messages (order confirmations, OTPs), promotional messages (offers, campaigns), and conversational messages (customer support). Channels include SMS, RCS, WhatsApp Business, Viber, and voice.

A carrier, also known as a mobile network operator (MNO), is a telecommunications company that owns and operates the wireless network infrastructure (radio towers, spectrum licenses, core network) used to deliver voice, data, and messaging services to subscribers. Examples include T-Mobile, Vodafone, and A1.

A Call Detail Record is a data record produced by a telephone exchange or switching system that documents the attributes of a call or messaging event — including originator, destination, timestamp, duration, and disposition. CDRs are essential for billing, fraud detection, traffic analysis, and regulatory compliance.

A chatbot is an automated software agent that simulates human conversation through text or voice interactions. In the messaging industry, chatbots are deployed over channels like WhatsApp, RCS, and Viber to handle customer support queries, process orders, provide information, and route complex issues to human agents — reducing response times and support costs.

A concatenated SMS is a long text message that exceeds the 160-character GSM limit (or 70 characters for Unicode) and is split into multiple message parts for transmission, then reassembled on the recipient's device. Each part is billed as a separate message segment, so a 300-character message using GSM encoding counts as two SMS segments.

In the mobile messaging ecosystem, a content provider is any business or organisation that originates A2P messages — such as banks sending OTPs, retailers sending promotions, or logistics companies sending delivery alerts. Content providers connect to messaging platforms like Bind to reach end users across channels.

Conversion rate measures the percentage of message recipients who take a desired action — such as clicking a link, completing a purchase, or redeeming a coupon. In messaging campaigns, conversion rates are a key performance indicator and are significantly influenced by channel choice, message timing, and personalisation.

CPaaS is a cloud-based platform that enables businesses to embed real-time communication capabilities — messaging, voice, video — into their own applications and workflows via APIs, without building or maintaining the underlying telecom infrastructure. CPaaS providers like Bind handle the complexity of carrier connections, routing, compliance, and delivery optimisation so businesses can focus on customer experience.

Delivery rate is the percentage of sent messages that are successfully delivered to the recipient's device. It is a critical metric for evaluating messaging performance. Factors that affect delivery rate include number validity, carrier filtering, network congestion, handset availability, and message content. Bind's Number Intelligence platform helps maximise delivery rates by verifying numbers before sending.

A Delivery Receipt (DLR) is a status notification returned by the mobile network confirming whether a message was successfully delivered to the recipient's handset, failed, or is still pending. DLRs provide transparency into message performance and are essential for SLA tracking, billing reconciliation, and campaign analytics.

In the context of telecom regulation — particularly in India — DLT refers to a blockchain-based registration system where businesses must register their sender IDs, message templates, and consent records before sending commercial messages. DLT registration is mandated by TRAI to combat spam and ensure messaging transparency.

E.164 is the international standard for telephone numbering plans, defined by the ITU. An E.164 number consists of a country code followed by the subscriber number, with a maximum length of 15 digits (e.g., +385911234567 for a Croatian mobile number). APIs and messaging platforms require E.164 format to ensure correct global routing.

Message encoding determines the character set used in an SMS, which directly affects message length. GSM 7-bit encoding supports 160 characters per segment using the standard Latin alphabet plus some symbols. Unicode (UCS-2) encoding supports characters from all languages — including Cyrillic, Arabic, Chinese, and emoji — but reduces the per-segment limit to 70 characters.

Failover is an automated routing strategy where, if a message fails to deliver via the primary channel (e.g., RCS), it is automatically rerouted to a fallback channel (e.g., SMS). Failover ensures maximum message reach and is a key feature of omnichannel messaging platforms.

A messaging firewall is a network security system that inspects, filters, and blocks fraudulent or unauthorised messaging traffic. SMS firewalls protect mobile operators from grey routes, spam, and revenue leakage. SS7 firewalls protect the signalling network from location tracking, call interception, and fraud attacks that exploit vulnerabilities in the SS7 protocol.

A Flash SMS (also called a Class 0 SMS) is a message that appears directly on the recipient's screen as a pop-up without being stored in the inbox. It requires the user to actively dismiss it. Flash SMS is used for urgent alerts, emergency notifications, and high-visibility messages where immediate attention is required.

A grey route is an unauthorised or semi-authorised path for delivering A2P messages that bypasses official carrier agreements, typically exploiting SIM farms or P2P channels to avoid termination fees. Grey routes are cheaper but unreliable, legally risky, and undermine operator revenue. Legitimate messaging providers like Bind use only direct, white-listed carrier connections.

GSM 7-bit encoding is the default character set for SMS, supporting 128 characters including the basic Latin alphabet, digits, and common punctuation. Messages using GSM encoding allow up to 160 characters per segment. Certain characters (like curly braces, euro sign, and square brackets) use an extended table and count as two characters.

An HLR lookup queries the mobile network's Home Location Register database to verify a phone number's status in real time — including whether the number is active, the current carrier, roaming status, and whether the handset is reachable. HLR lookups are used to clean contact lists, reduce undeliverable messages, and improve campaign efficiency.

IMSI is a unique identifier stored on a SIM card that identifies a mobile subscriber within a GSM or LTE network. It is used by the network for authentication and routing. IMSI consists of a mobile country code (MCC), mobile network code (MNC), and a unique subscriber number.

IVR is an automated telephony system that interacts with callers using pre-recorded voice prompts and DTMF keypad input or speech recognition. IVR systems are used for call routing, account balance inquiries, appointment scheduling, and survey collection — reducing the need for live agents while providing 24/7 availability.

In messaging, latency is the time delay between when a message is submitted to the platform and when it is delivered to the recipient's device. Low latency is critical for time-sensitive use cases like OTP delivery, where even a few seconds of delay can cause authentication failures and poor user experience.

A long code is a standard 10+ digit phone number (in E.164 format) used for sending and receiving messages. Unlike short codes, long codes are not designed for high-throughput bulk messaging but are commonly used for two-way conversational messaging, local presence, and smaller-scale A2P campaigns.

Mobile Country Code (MCC) and Mobile Network Code (MNC) are numerical identifiers that together uniquely identify a mobile carrier within a specific country. For example, MCC 219 identifies Croatia, and MNC 01 identifies T-Mobile Croatia. These codes are used in number lookups, routing decisions, and regulatory compliance.

Throughput is the number of messages a platform or connection can process per second (MPS). High throughput is essential for time-critical use cases like flash sales, event-triggered OTPs, and emergency alerts. Bind's infrastructure is engineered for sustained high throughput with automatic scaling during traffic spikes.

MNP is the regulatory mechanism that allows mobile subscribers to switch carriers while keeping their existing phone number. MNP complicates message routing because the number's original carrier prefix no longer reliably indicates the current carrier. Real-time portability lookups — like those provided by Bind's Number Intelligence platform — resolve the current carrier to ensure correct routing.

MO (Mobile-Originated) refers to messages sent from a mobile user's handset to an application or service. MT (Mobile-Terminated) refers to messages sent from an application to a mobile user's handset. Most A2P messaging is MT traffic, while MO traffic enables two-way communication such as keyword-triggered opt-ins, surveys, and support requests.

MSISDN (Mobile Station International Subscriber Directory Number) is the full international phone number associated with a mobile subscription — essentially the phone number a user dials. It is formatted according to the E.164 standard and is the primary identifier used to route messages and calls to a specific subscriber.

Number Intelligence is a suite of real-time lookup services that validate and enrich mobile phone number data. Capabilities include verifying whether a number is active, determining the current carrier (even after porting), checking roaming status, and assessing number credibility for fraud scoring. Bind's Number Intelligence platform helps businesses reduce costs by avoiding messages to invalid numbers and improves security through pre-send validation.

Omnichannel messaging is a strategy that delivers a unified, consistent customer experience across multiple communication channels — SMS, RCS, WhatsApp, Viber, voice, email — while maintaining conversation context as customers move between them. Unlike multichannel (which operates channels in silos), omnichannel integrates channels so that a conversation started on WhatsApp can continue seamlessly via SMS or voice.

Opt-in is the process by which a user explicitly consents to receive messages from a business, typically via a web form, keyword SMS, or checkbox. Opt-out is the mechanism for a user to withdraw that consent, usually by replying STOP or clicking an unsubscribe link. Maintaining compliant opt-in records and honouring opt-out requests immediately is a legal requirement under GDPR, TCPA, and most national telecom regulations.

An OTP is a temporary, single-use code — typically 4 to 8 digits — sent via SMS, voice, or messaging app to verify a user's identity during login, transaction confirmation, or account recovery. OTPs are the most common form of 2FA and represent one of the largest A2P traffic categories globally. Delivery speed and reliability are critical, as OTPs typically expire within 30 seconds to 5 minutes.

OTT messaging refers to communication services delivered over the internet rather than through the carrier's own messaging infrastructure. WhatsApp, Viber, Telegram, and Facebook Messenger are all OTT platforms. For businesses, OTT channels offer rich media capabilities, read receipts, and interactive elements that traditional SMS cannot provide — but require the recipient to have the app installed.

Person-to-Person (P2P) messaging is communication between two individual mobile users — the standard text message between friends, family, or colleagues. P2P traffic is distinguished from A2P traffic in carrier billing and regulatory frameworks, and carriers actively detect and block A2P messages disguised as P2P to prevent grey-routing.

A portability lookup determines the current serving carrier for a mobile number, regardless of the number's original carrier assignment. This is essential in countries with active MNP (mobile number portability) because a number's prefix no longer reliably indicates the carrier. Accurate portability data ensures correct routing and avoids sending messages through the wrong network.

RCS is the next-generation messaging protocol designed to replace SMS as the default messaging standard on mobile devices. Built into the native messaging app (no separate download required), RCS supports rich media (images, video, carousels), interactive buttons, branded sender profiles with verified business identity, read receipts, and typing indicators. RCS combines the universal reach of SMS with the rich experience of OTT apps.

A REST (Representational State Transfer) API is an architectural style for web APIs that uses standard HTTP methods (GET, POST, PUT, DELETE) to perform operations on resources identified by URLs. Most modern messaging APIs — including Bind's — follow REST conventions, making them straightforward to integrate into any programming language or platform that can make HTTP requests.

Rich media in messaging refers to content beyond plain text — including images, video, audio, GIFs, carousels, interactive buttons, location pins, and file attachments. Rich media is supported by RCS, WhatsApp Business, and Viber, and significantly increases engagement and conversion rates compared to text-only SMS.

Sender ID is the name or number displayed as the message sender on the recipient's device. It can be a short code, long code, or an alphanumeric string (e.g., "BindTech"). Alphanumeric sender IDs enhance brand recognition but are one-way (recipients cannot reply). Sender ID regulations vary by country — some require pre-registration, others restrict alphanumeric IDs entirely.

A short code is a shortened phone number (typically 4–6 digits) used for high-volume, high-throughput A2P messaging. Short codes are pre-approved by carriers, support much higher message-per-second rates than long codes, and are commonly used for marketing campaigns, voting systems, and premium messaging services. They are country-specific and require carrier approval.

A SIM farm is a collection of SIM cards installed in specialised hardware (SIM boxes) used to route A2P traffic through P2P channels, bypassing official carrier interconnects and avoiding termination fees. SIM farms are a form of grey routing, are illegal in most jurisdictions, and are actively detected and blocked by carrier firewalls.

Smart routing is the automated selection of the optimal delivery path for each message based on factors like cost, carrier performance, delivery speed, number portability data, and channel availability. A smart routing engine dynamically adjusts routes in real time to maximise delivery rates and minimise costs.

SMPP is the industry-standard protocol used for exchanging SMS messages between message centres (SMSCs) and messaging platforms. It provides a persistent, high-speed connection for submitting and receiving messages, querying message status, and managing delivery receipts. SMPP is used by enterprises and aggregators requiring high throughput and fine-grained control over message handling.

SMS is the foundational text messaging protocol, standardised as part of the GSM specification. Each SMS supports up to 160 characters in GSM encoding (70 in Unicode). Despite being a 30+ year old technology, SMS remains the most universally available messaging channel — working on every mobile phone without requiring a data connection or app installation — making it the ultimate fallback channel in omnichannel strategies.

The SMSC is the network element within a carrier's infrastructure responsible for storing, forwarding, and delivering SMS messages. When you send an SMS, it passes through the originating carrier's SMSC, which handles routing to the recipient's network and manages retry logic for temporarily unavailable handsets.

SS7 is the set of signalling protocols used by telephone networks worldwide to exchange control information — setting up and tearing down calls, routing SMS, managing number portability, and enabling roaming. Because SS7 was designed in the 1970s without security in mind, it contains well-known vulnerabilities that can be exploited for location tracking, call interception, and fraud. SS7 firewalls are essential for protecting networks against these threats.

Throughput in the messaging context is the rate at which a system can process messages, typically measured in messages per second (MPS). Platform throughput determines how quickly a business can deliver time-sensitive campaigns, OTPs, or alerts to large audiences. Bind's infrastructure is designed for high sustained throughput with burst capacity for peak traffic.

Transactional messages are triggered by a user action or system event — such as a purchase confirmation, password reset OTP, shipping notification, or account alert. They are distinguished from promotional messages in that they are expected by the recipient and typically exempt from marketing consent requirements (though they must still comply with data protection regulations).

Two-way messaging enables both sending and receiving messages between a business and its customers. This supports interactive use cases like customer support conversations, opt-in/opt-out management via keyword replies, surveys, appointment confirmations, and feedback collection. Two-way messaging requires MO (mobile-originated) message handling capabilities.

Unicode (specifically UCS-2 encoding in SMS) is the character encoding standard that supports characters from virtually all writing systems — including Cyrillic, Arabic, Chinese, Korean, Hindi, and emoji. Using Unicode in an SMS reduces the per-segment character limit from 160 to 70, meaning messages with even a single non-GSM character (like an emoji or accented letter outside the GSM set) will be encoded as Unicode and may result in additional message segments.

A verified sender is a business identity that has been authenticated and approved by a messaging platform or carrier, displaying a brand name, logo, and verification badge to the message recipient. Verified sender profiles are available on RCS and WhatsApp Business, and they significantly improve open rates and trust by helping recipients distinguish legitimate business messages from spam or phishing.

Viber Business Messages allow companies to send transactional and promotional messages to Viber users through the Viber for Business platform. Features include rich media support, branded sender profiles, interactive buttons, two-way conversations, and delivery/read receipts. Viber is particularly strong in Central and Eastern Europe, Southeast Asia, and parts of the Middle East.

Text-to-Speech voice messaging converts written text into spoken audio and delivers it as an automated phone call. TTS is used for OTP delivery via voice (as a fallback when SMS is unavailable), appointment reminders, emergency alerts, and accessibility-focused notifications. Modern TTS engines support multiple languages, natural-sounding voices, and SSML markup for pronunciation control.

A webhook is an HTTP callback — an automated message sent from one application to another when a specific event occurs. In messaging platforms, webhooks are used to receive real-time delivery receipts, incoming message notifications, and status updates without needing to repeatedly poll the API. Bind's API supports webhook configuration for DLRs, MO messages, and authentication events.

The WhatsApp Business API enables medium and large businesses to send and receive messages at scale on WhatsApp — the world's most-used messaging app with over 2 billion users. It supports rich media, interactive list and button messages, message templates for outbound notifications, and end-to-end encryption. Businesses access the API through authorised Business Solution Providers (BSPs) like Bind.

A white route is an authorised, officially sanctioned path for delivering A2P messages, established through direct interconnect agreements between the messaging provider and the carrier. White routes ensure message delivery complies with carrier policies, regulatory requirements, and quality standards — resulting in higher delivery rates, better sender reputation, and full DLR transparency.

Zero Trust is a security framework based on the principle of "never trust, always verify" — no user, device, or network segment is inherently trusted, even inside the corporate perimeter. In the context of messaging and telecom platforms, Zero Trust principles are applied to API authentication, network segmentation, SS7 traffic inspection, and access control to protect against both external attacks and insider threats.