A founder (and a friend) of a newly started startup spent almost a month arguing with her co-founder about something interesting. She wanted to allocate a large budget on email because, in her words, “email is aged, low cost and a trusted channel.” But he was pushing for WhatsApp because “that’s what is a trend these days”. Neither brought up SMS until their newly hired growth guy pulled out ROI data from a test he’d run in his previous job comparing Email, WhatsApp and SMS or even push notifications.
SMS on.
That surprised both of them, and honestly it surprises most startup founders the first time they see the data.
Here’s the usual mistake they all make – they compare channels solely by what it costs to hit send. Email costs next to nothing, SMS costs a few paisa per unit, and WhatsApp sits premium and high. If you go by price upfront, email wins every single time, no contest.
But that’s not why you buy a cPaaS channel. You are paying for the highest ROI possible – what you spend divided by what you gain. This means not just immediate revenue, but also your brand reputation and long-term customer value.
What Happens Once You Send?
Let’s break it down channel by channel.
Email marketing
You blast all campaigns to your whole list and then you get 20 to 30% open rate and the clickthroughs are a fraction of that. The aggressive spam filters, bad subject lines and content, misaligned user expectations, weak CTAs, over emailing, etc. all contribute to the bad results.
Consequently, your cost per conversation quietly goes high.
WhatsApp is great for capturing attention, no argument on that. Unlike email, it has about a 70% open rate which is interesting. In fact, people are glued to it all the time. However, the total cost – including setup fee, service fee, monthly maintenance, no. of agents, features – it all sums to pretty big.
For promotional broadcasting, the price goes around ₹0.90 per message in India while utility messages cost a bit higher than a standard SMS.
Plus, WhatsApp Business API service in India is tougher than it looks – your business account can be restricted or blocked overnight sometimes with zero warning, if enough users report you or Meta updates its policy, which they do all the time. It is like you sent a campaign last evening and the next morning you wake up – your entire channel is just gone.
SMS
SMS is the odd one out. It costs more per unit compared to email but it drives better results. The open rates are nearly 100% in basically every report I’ve seen, and the messages get seen instantly, in the first few minutes after delivery, not hours or days later. Not every provider stays true to their promise though, some bulk SMS providers are faster and more reliable than others, which is worth checking before you commit.
There’s no algorithm deciding whether the message is worth showing you or not. It shows up – for every person, whether they’re on a smart phone or keypad phone.
Email Vs WhatsApp Vs SMS – In Numbers
Suppose a campaign sending out to 10,000 people.
Email costs somewhere between Rs.2000 to 10,000 depending on complexity of personalization and assets you need, the software quality and the sophistication of your campaigns. You also need to build a healthy email list and verify it from time to time. If you choose monthly billing over annual, the price goes higher – which means you’re paying more without sense.
WhatsApp might reach 5k to 6k people out of that 10,000, thanks to the trust WhatsApp built over years with Indian consumers. However, once you consider template fee, conversational charges, and maintenance fee, it would eat all your budget.
SMS, at a higher per-unit cost compared to email, might land in 9,000 or even full and get read 100%. Even If 500 people act on it because they recognize your brand, the ultimate cost per conversion is less than email’s. Best of all, SMS doesn’t force you into long-term contracts unless you want it – you can always start small and upgrade as you grow.
Successful founders figured this out – cheap and cost effectiveness are not the same thing in the business world.
So which one do you actually use?
Instead of choosing one channel and dropping others, the smart thing to do is integrate all three into your marketing strategy. Each has its own benefits and cons. Your choice should depend totally on your budget and business goals.
Email is great for nurturing long-term customer relationships, broadcasting long-form tutorials and weekly/monthly newsletters and sharing content where the reader has time to engage and is not expected to engage instantly.
WhatsApp is ideal for quick updates, support chats, and multimedia marketing. Unlike SMS, it makes communication one-way to interactive, making it an engaging cPaaS channel.
SMS is perfect when speed and data certainty is crucial. OTPs, payment confirmation, delivery alerts, quick reminders, flash sale, etc.
As a startup founder, you don’t need to do deep math and pick a winner right away. You need a balanced communication channel stack where every tool is doing its job.
Final word
As you reach this point, I want to say something important and it rarely comes up until it happens. Email deliverability can take a hit if your domain reputation takes a hit from continuous blocks and reports. WhatsApp can be vanished overnight with a new policy or spam reporting.
And that is not the case with SMS, although DLT registration can be a little overwhelming and the stability and security is worth putting SMS on top of the list.
So if you are wondering where you should spend your precious funding or bootstrapped capital, stop looking for the “Cheapest” options and understand things like “Reliability and ROI.” Start small, run small tests across all three channels, track open rates and clickthroughs, and decide what works best for you and customers in the long run.
