SMS, RCS and WhatsApp all put a message on your customer’s phone, but they reach different people, show different things and cost different amounts. This guide compares them side by side and shows which to use for common jobs, and when to use more than one.
In short: SMS reaches every mobile phone, with or without data, so it’s the safe choice for critical alerts and passcodes. RCS turns a text into a branded, verified, interactive message in the same inbox, with SMS as a fallback. WhatsApp is best for conversations with customers who use it and have opted in. Most organisations get the best results by combining them.
At a glance
| SMS | RCS | ||
|---|---|---|---|
| Where it arrives | The phone’s messaging app | The phone’s messaging app | The WhatsApp app |
| Who can receive it | Every mobile phone | Android phones and iPhones on iOS 18 or later, where the network supports RCS | People who use WhatsApp and have opted in to your messages |
| Needs mobile data or wi-fi | No | Yes | Yes |
| Sender shown | A sender name (up to 11 characters) or a phone number | Your verified brand name, logo and colour | Your verified business profile |
| Content | Plain text | Text, images, video, rich cards, carousels and buttons | Text, images, documents, video, audio and buttons |
| Message length | 160 characters per part; longer messages are joined | Up to 3,072 characters of text | Up to 4,096 characters of text |
| Starting a conversation | Any time (with consent for marketing) | Any time (with consent for marketing) | Approved templates only, unless the customer messaged you in the last 24 hours |
| Receipts | Delivered | Delivered and read | Delivered and read |
| If it can’t be delivered | – | Fall back to SMS or a web version | Fall back to SMS or another channel |
| Best for | Universal alerts, passcodes, critical messages | Branded, interactive journeys in the native inbox | Conversations and customer service with opted-in customers |
SMS: reaches everyone
SMS works on every mobile phone in the country, old or new, and doesn’t need mobile data, wi-fi or an app. Messages arrive in seconds, and almost all are read. That makes SMS the dependable choice when a message simply has to get through: passcodes, outage and emergency alerts, delivery and appointment reminders.
- Strengths: universal reach, no app or data needed, fast, simple, and supported by every business system.
- Limits: plain text only, 160 characters per message part, and a sender that can be imitated by scammers. In the UK, the SMS SenderID Protection Registry helps stop criminals using registered brand names.
- Cost: charged per message part, typically a few pence in the UK. Long messages and emoji use more parts, so it pays to understand SMS character limits.
RCS: SMS, upgraded
RCS (Rich Communication Services) Business Messaging arrives in the same messaging app as SMS, but the sender is a verified brand with your name, logo and colours. Messages can include images and video, rich cards with buttons, swipeable carousels, and suggested replies such as “Confirm” or “Reschedule” that customers tap instead of typing.
- Strengths: a trusted, branded sender that is hard to imitate; rich, interactive content in the inbox customers already use; and read receipts, so you know a message was seen, not just delivered.
- Limits: the phone, the network and a data connection all need to support it. Android phones support RCS through Google Messages, and Apple added it to iPhone with iOS 18.
- Fallback: anyone who can’t receive RCS gets an SMS instead, or an SMS with a link that shows the same rich message as a branded web page, so nobody misses out.
- Cost: charged per message, with plain-text RCS usually close to the price of an SMS and rich messages costing more. Fallback messages are charged as SMS.
Read more about RCS Business Messaging with everymessage.
WhatsApp: built for conversation
WhatsApp Business messages arrive in the WhatsApp app, from your verified business profile. They support text, images, documents, voice notes and buttons, and they suit two-way conversations: customer service, bookings and support.
- Strengths: very widely used in the UK and worldwide, great for back-and-forth conversations, and inexpensive for reminders, passcodes and replies to customers who message you first.
- Limits: customers must use WhatsApp and opt in to messages from you. To start a conversation you must use a template approved by WhatsApp, and free-form messages are only allowed for 24 hours after the customer’s last message.
- Privacy: Meta runs the platform and handles message content, so avoid sending medical or financial details by WhatsApp.
- Cost: Meta’s fee per message, which depends on the message category, plus our usage fee. See WhatsApp message types and pricing explained.
Which channel for which job?
| Job | Best choice | Why |
|---|---|---|
| One-time passcodes | SMS, or WhatsApp with SMS fallback | SMS reaches every phone instantly. WhatsApp authentication messages can cost less for customers who use it. |
| Appointment reminders | RCS with SMS fallback | Branded reminder with “Confirm” and “Reschedule” buttons, while SMS covers everyone else. |
| Delivery updates | RCS or WhatsApp, with SMS fallback | Images, tracking buttons and maps make updates clearer. |
| Marketing campaigns | RCS with fallback, or SMS | Carousels and images from a verified brand stand out; SMS is simple and reaches everyone. WhatsApp marketing costs more and needs opt-in. |
| Customer service | WhatsApp, or RCS | Customers can start a chat from your website, an email or an SMS link, and replies in the 24-hour window cost little. |
| Emergency and outage alerts | SMS | Works without data or an app, on every phone, even when networks are busy. |
| Sensitive information | SMS or RCS with a secure link | Send a notification and link to a secure portal rather than the details themselves. |
Using them together
You don’t have to choose one channel. The most effective set-ups use each where it’s strongest:
- RCS first, SMS fallback. Send a branded, interactive message; anyone who can’t receive RCS automatically gets an SMS or a web version, so you reach everyone.
- WhatsApp where customers prefer it. Use WhatsApp for customers who have opted in, and for conversations they start.
- SMS for the critical path. Keep SMS for passcodes and urgent alerts, where reaching every phone matters more than looks.
- Journeys across channels. With Workflow, follow an unread message with a reminder on another channel, or an email, or a call.
everymessage runs SMS, RCS, WhatsApp and email from one platform, one inbox and one API, with delivery reporting for every channel.
Frequently asked questions
What is the difference between RCS and SMS?
SMS is plain text from a number or sender name and works on every mobile phone. RCS arrives in the same messaging app but comes from a verified brand with your logo, and can include images, rich cards, carousels and buttons. It needs a phone and network that support RCS and a data connection; when it can’t be delivered, an SMS can be sent instead.
Is RCS available on iPhone?
Yes. Apple added RCS to iPhone with iOS 18, and Android phones support it through Google Messages, where the mobile network supports it. Phones that can’t receive RCS can get an SMS or a web version instead.
Is WhatsApp cheaper than SMS for businesses?
For utility and authentication messages, such as reminders and passcodes, usually yes in the UK. Marketing messages on WhatsApp cost more, and every recipient must have WhatsApp and have opted in to hear from you.
Which channel is best for one-time passcodes?
SMS reaches every phone without needing data or an app, so it remains the safest default. WhatsApp authentication messages can cost less for customers who use WhatsApp, with SMS as the fallback.
Can I use more than one channel?
Yes. With everymessage you can send by RCS with automatic SMS fallback, use WhatsApp for customers who have opted in, and run all three from one platform, inbox and API.
Not sure which channel to use?
Tell us what you need to send and to whom, and we’ll recommend the right mix.