No More Cold Calls: How Your Sales & Marketing Teams Use WhatsApp Business Calling API for Warm, Permission-Based Conversations

From Unknown Numbers to Recognised Conversations

Cold calls from unknown numbers are getting worse every year: low pick-up rates, low trust, and a lot of wasted sales time. People ignore unfamiliar numbers, hang up quickly, or feel they’re being interrupted, not helped.

On WhatsApp, the dynamic flips. Customers recognise your brand name, logo, and verified profile. In many cases, they message you first or tap a button to agree to a follow-up call. With WhatsApp Business Calling API, sales and marketing teams can turn “interruptive” outbound calls into warm, permission-based conversations that are directly connected to the campaign, ad or message that started the journey.

Why Warm WhatsApp Calls Beat Classic Cold Calling

Warm leads only

Every call is preceded by at least one WhatsApp interaction: a click-to-WhatsApp ad, a reply to a broadcast, a form follow-up in chat, so your team doesn’t waste time on uninterested contacts.

Higher trust

Calls come from a recognisable, verified WhatsApp Business profile, not a random phone number. Prospects know who is calling and why. After the conversation, they can scroll back through the chat thread to re-read details, links and prices instead of trying to remember what was said.

Higher customer quality

A WhatsApp chatbot can qualify leads in chat first (intent, budget, timeline, product interest) before anyone picks up the phone. By the time sales gets involved, they are speaking to people who match your target profile.

Better measurement

Because everything happens inside WhatsApp, you can tie calls back to:

• The campaign, ad set, keyword or audience that generated the lead.
• The specific broadcast, flow step or tag that led to “Call me”.

This makes it easy to compare “message-only” vs “message + call” funnels and optimise both media spend and sales effort.

Your WhatsApp Business Profile as Your “Public Number”

The foundation of “no more cold calls” is simple: put one verified WhatsApp Business account at the centre of all your campaigns, and treat it as your public number.

Use your official WhatsApp Business account as the main contact point and display the WhatsApp number / QR code / click link across:

• Website headers/footers and landing pages (“Chat with us on WhatsApp”).
• Click-to-WhatsApp ads on Meta and other platforms.
• Physical stores, product packaging, brochures, invoices, receipts and events.

Why this matters:

• When you contact them via WhatsApp Business Calling API, customers see a known, branded WhatsApp account, not a random mobile number.
• They are more likely to pick up, because they have already messaged you, saved the contact, or seen your profile in a previous campaign.

Instead of 10 different outbound numbers, you build one trusted WhatsApp entry point for all conversations and calls, and every interaction adds to the same relationship, not a scattered list of one-off phone calls.

Replace Cold Calls with “Call Me” Journeys from Campaigns

Click-to-WhatsApp Ads → Chat → Call

Campaign flow:

1. A user taps a click-to-WhatsApp ad and lands in a WhatsApp chat with your brand.
2. A short welcome flow asks 2–4 quick questions: what they’re interested in, budget range, timeline, location, or other qualifiers.
3. Once you have enough context, offer two clear options:
   • “Get details here in chat”
   • “Book a quick WhatsApp call with our team”

If they choose a call, ask for a preferred time window (“Now”, “Today 3PM”, “In 15 minutes”) and confirm in chat. The sales rep then calls from the same thread, with the answers on screen, and sends a recap + links afterwards.

Marketing value:

• Every call is traceable back to a specific ad, audience, creative and landing journey.
• Sales only calls leads who have answered at least 1–2 questions and explicitly opted in, instead of calling every lead on a list.

Broadcasts & Flows with “Call Me” Buttons

Typical use cases:

1. New product launches and upgrades.
2. Seasonal promotions.
3. VIP previews and loyalty benefits.
4. Renewal, cross-sell and upsell campaigns.

Flow:

1. Send a targeted WhatsApp broadcast to a segment (e.g. past buyers, near-renewal customers, high-intent leads).
2. Include interactive buttons such as:
   • “Talk to an advisor”
   • “Call me about this offer”
   • “Book a WhatsApp call”
3. When a user taps the button:
   • Your system creates a task or deal in the CRM.
   • The assigned agent calls back via WhatsApp Business Calling API from the same conversation, with full campaign context visible.
   • After the call, the agent logs the outcome and sends a quick summary + link in the thread.

You never auto-dial people from a cold list. You invite them to ask for a call, and your team responds only to those who do.

Real-World Marketing Examples

Education: Universidad Uk

Online university Universidad Uk wanted to shorten the time between digital campaign lead and meaningful conversation, so they could boost engagement and increase the chances of enrolling those leads as students.

• Click-to-WhatsApp ads push prospects into WhatsApp chat
• The school representative screens each person by asking them questions to determine their needs and learn which classes they are interested in taking.
• Agents can choose to send a WhatsApp message that gives prospective students the option to voice call the representative directly from the same WhatsApp thread to learn more or enroll.

• Lead reply rate for WhatsApp has increased by 1.5 percentage points, a higher increase than its other communication channels during the same time period.
• Leads who speak with Universidad Uk via WhatsApp Business Calling API stay on the phone with the school longer on average than leads reached through traditional voice channels.

Membership & Consumer Services: Cartão de Todos

Context: Discount card provider Cartão de Todos noticed that some customers stopped responding when a sales or support representative offered to call them to talk more about the product or resolve their issue

Solution: The company implement WhatsApp Business Calling API, which enabled agents to conveniently make phone calls to customers directly within WhatsApp, saving time and increasing the chances of the customer being available to speak. 

Outcome: Over one month (May 9–June 8, 2025), Cartão de Todos reported these improvements, all attributed to WhatsApp Business Calling API:

• 26% increase in conversions
• 50% estimated decrease in average conversion time
• 9-point increase in Net Promoter Score

By turning cold telemarketing into opt-in, in-thread WhatsApp calls, Cartão de Todos made each call more relevant, more convenient, and easier to track.

How Sanuker & WOZTELL Help Marketing Turn Calls into a Funnel

To shift cold calls to warm calls, you need more than a feature, you need a funnel. With Sanuker and our platform WOZTELL, your teams can:

• Set up click-to-WhatsApp ads, broadcasts and flows with “Call me” actions built into the journey.
• Allow sales reps initiate WhatsApp calls from the same conversation where the lead started, while automatically logging results and notes.
• Sync campaign and call data to your CRM and analytics, so you can report by source, segment, agent, and see exactly which journeys turn messages into revenue.

If your team is still dialling from unknown numbers, it might be time to give your campaigns a WhatsApp-native way to talk. Sanuker can help you design and implement journeys with WhatsApp Business Calling API, starting from a single pilot campaign and scaling up once you see the results.