Most businesses run three separate tools: one for SMS, one for WhatsApp, one for email. The result is that the same customer gets the same message three times, and no single report tells you which channel actually drove the sale. Mersal's unified campaign fixes this at the root: you write the message once, pick your channels, and the platform handles the rest.
How a unified campaign works
From Dashboard → Campaigns you start a new campaign and move through four steps:
- Content: a message editor with a live preview of how the message will look on WhatsApp before you send it.
- Audience: pick a contact group, or filter by custom attributes (city, last purchase, customer type).
- Channels and gateways: choose SMS and/or WhatsApp and/or email, and select the gateway for each.
- Timing: send now, or schedule with quick presets (tomorrow morning, next week…).
Why one channel isn't enough
Each channel has a different strength, and relying on just one means losing part of your audience:
- SMS reaches any phone, even without internet — best for urgent alerts and verification codes.
- WhatsApp delivers the highest read rates and supports images, video, buttons and interactive lists.
- Email is the natural home for long-form content, invoices and catalogues.
"All channels" versus "one after another"
There are two ways to run a unified campaign, and most people conflate them:
- Parallel send: the same message goes to all three channels at once. Right for major announcements where you want maximum reach in a short window — but you pay for three channels per customer.
- Sequential send (fallback): WhatsApp first, and if it isn't delivered within your chosen window it switches to SMS. This suits most cases: nearly the same reach at far lower cost.
The practical rule: parallel for the rare, very important campaign; sequential for everything else.
One message across three channels
The same text doesn't work everywhere. Watch for:
- SMS length: Arabic messages split every 70 characters. A 280-character message is 4 messages and 4× the cost. Write a shorter SMS variant.
- Links: in email a link hides behind text; in SMS it's written out and eats space. Use a short tracking domain.
- Media: WhatsApp and email support images, SMS doesn't. Make sure the message still makes sense without the picture.
- Subject line: email only — leave it empty and the whole campaign is wasted.
The recipient guard
One of the most expensive mistakes is launching a campaign with no audience selected. Mersal runs a validation guard across every send form that blocks a launch when recipients are empty — so you can never lose a campaign you spent an hour writing.
Rate limits
For every gateway you can cap sends per minute, per hour and per day. This isn't optional polish: a sudden burst from a fresh WhatsApp number is the fastest route to a ban. Start with low limits and raise them gradually over the first couple of weeks.
Note how the daily cap interacts with scheduling: a campaign to 10,000 contacts at 500 a day takes 20 days. If the offer expires in a week, either add more connected numbers or narrow the audience.
Measurement
After launch you get one unified report per channel: sent, successful, pending, failed — plus a separate credit log for each channel. If your plan includes campaign intelligence you also get Insights, A/B testing, and a send-time optimiser that suggests the best window based on how your audience actually engages.
The numbers to compare channels on
Delivery rate alone is misleading, because email delivers 98% and gets read 20%. Compare in this order:
- Delivery rate: a technical health signal — a drop means a gateway or list problem.
- Read or open rate: the first real measure of interest.
- Click or reply rate: this is what actually measures the content.
- Cost per click: channel credit ÷ clicks. The only figure that compares differently-priced channels fairly.
You will usually find email cheapest per message and WhatsApp cheapest per click — and that is what should change your decision.
Common mistakes
- Sending the identical text across all three channels without shortening the SMS variant.
- Running parallel sends by default — paying three times for one customer.
- Launching a large campaign with no rate limits on a new WhatsApp number.
- Comparing channels on delivery rate alone.
- Not excluding people who opted out of a specific channel — an email unsubscribe is not consent for WhatsApp.
Where to start
Begin with a small campaign to a limited group (50–100 contacts) across two channels, and compare. Then scale. The real value of unified campaigns shows up once you have enough data to compare channels on the same message and the same audience.
Frequently asked questions
If a customer has both an email and a number, do they get it twice? In parallel mode, yes. In sequential mode, no — the second channel only fires if the first one failed.
Can I stop a running campaign? Yes, pause or cancel it; credit for unsent messages is returned.
Is the balance shared across channels? The balance is shared, but consumption is logged per channel so you can see where it went.
