For Sri Lankan businesses, with Notify.lk Meta Tech Partner

WhatsApp Business API for Sri Lanka

Send OTPs, order updates and reminders on WhatsApp with one REST API. Track every message with delivery webhooks, and answer customer replies in a shared inbox. Built by Chateta, in partnership with Notify.lk.

Book an onboarding call Early access via Notify.lk

From €9.99/month (≈ Rs. 3,750). Meta bills its message fees to you directly.

New

From 1 October 2026, Sri Lanka has its own, lower Meta rates for utility and authentication messages, the ones behind OTPs and order alerts. See Meta's pricing

Nuwara Stores

Business account

Today

482913 is your verification code. For your security, do not share this code.

10:02

Copy code

Your order is on its way

Hi Nimal, order #4821 is out for delivery and should reach you today before 6 pm.

10:11

Track order

Can you deliver after 6? I'm at work until then.

10:14

message.read → your webhook Reply → your Chateta inbox
Why WhatsApp

Transactional messages people actually open

Your customers already use WhatsApp every day. Here is what it adds to an OTP or an order update that an SMS can't.

Your verified business name

Messages arrive from your business profile with your name and logo, not an unknown number or a sender ID customers have learned to ignore.

Buttons customers can tap

Add Confirm, Cancel or Track order buttons, a copy-code button on OTPs, and images or PDF invoices in the message header.

Delivered and read receipts

See when each message was sent, delivered and read, by API or by webhook, so you know an OTP actually reached the customer.

Customers can reply

A delivery question or a reschedule request comes straight back to your team in the Chateta inbox, instead of a phone call.

Use cases

Built for the messages your customers wait for

OTP and login codes

Send one-time passwords with an authentication template. Pass the code once and Chateta fills in the copy-code button for you.

Order and delivery alerts

Order confirmed, packed, out for delivery. For online stores and couriers, with a Track order button and replies to your team.

Appointment reminders

Clinics, salons and schools send a reminder with Confirm and Reschedule buttons, and fewer people miss their slot.

Payment and due-date reminders

Remind customers before a bill is due and attach the invoice as a PDF, so they have everything they need to pay.

SMS or WhatsApp?

An honest comparison

WhatsApp is not a cheaper SMS. It is better for some messages and worse for others, so most businesses use both.

SMS (Notify.lk)
WhatsApp (Chateta)
Reaches
Every mobile phone
Phones with WhatsApp
Shown as
Your sender ID
Your verified business profile
Buttons, images and PDFs
No
Yes
Receipts
Delivery reports
Delivered and read
Customer replies
Not to a sender ID
Straight to your inbox
Cost per message
Low and flat
Set by Meta per category. Marketing messages cost many times an SMS

Keep SMS for

Bulk promotions, and customers on phones without WhatsApp. A WhatsApp marketing message costs many times an SMS, so promo-heavy senders should stay on SMS.

Use WhatsApp for

OTPs, order and delivery alerts, reminders, and any message where the customer might want to reply or tap a button.

Best of both

Coming soon

Send on WhatsApp first and fall back to SMS through your own Notify.lk account if the message can't be delivered.

How it works

From SMS API to WhatsApp in four steps

1

Connect your number

Link a Sri Lankan (+94) number to WhatsApp through Meta. Meta verifies your business once, and we guide you through it.

2

Get templates approved

Write your OTP, order and reminder messages as templates. Meta reviews most templates within 24 hours.

3

Send through the API

One POST request per message with your API key. Track delivery by webhook or by polling the message.

4

Handle replies

Replies land in your Chateta inbox for your team to answer. Replies by webhook to your own system are coming soon.

Webhook coming soon
For developers

If you can send an SMS, you can send a WhatsApp

Same idea as the Notify.lk API: one HTTPS request per message. Chateta adds JSON, idempotent retries and signed status webhooks.

Today: an OTP by SMS with Notify.lk

curl https://app.notify.lk/api/v1/send \
  -d user_id=YOUR_USER_ID \
  -d api_key=YOUR_API_KEY \
  -d sender_id=YourBrand \
  -d to=94771234567 \
  -d message="Your login code is 482913"

With Chateta: the same OTP on WhatsApp

curl https://app.chateta.com/api/messaging/v1/messages/template \
  -H "Authorization: Bearer chk_YOUR_API_KEY" \
  -H "Idempotency-Key: login-8412-482913" \
  -H "Content-Type: application/json" \
  -d '{
    "to": "+94771234567",
    "template": "login_code",
    "language": "en",
    "parameters": ["482913"]
  }'

login_code is an authentication template. Pass the code once in parameters and Chateta also fills in the copy-code button. The request returns 201 with a message id to match against webhooks.

Then Chateta calls your webhook as the status changes

POST https://your-app.lk/webhooks/chateta
X-Chateta-Signature: t=1790829127,v1=5f2c9a…

{
  "id": "0f8a61c2-…",
  "type": "message.delivered",
  "created_at": "2026-10-01T04:32:07+00:00",
  "data": {
    "message": {
      "id": "9b1d7e40-…",
      "status": "delivered",
      "type": "template",
      "to": "+94771234567",
      "delivered_at": "2026-10-01T04:32:07+00:00"
    }
  }
}

Events: message.sent, message.delivered, message.read and message.failed.

  • Idempotency-Key

    Retry safely. Repeating a request with the same key returns the original message instead of sending twice.

  • X-Chateta-Signature

    Every webhook is HMAC-signed, so you can check it came from Chateta.

  • GET /templates

    List your approved templates and the parameters and header each one needs.

  • POST /messages/text

    Send free-form text inside the 24-hour window after a customer messages you.

  • header

    Add an image, video or PDF document to a template by HTTPS link.

  • GET /messages

    Filter your sends by status, recipient and date for reporting and support.

  • Replies land in the inbox. When a customer answers, the conversation opens in your Chateta inbox with your earlier API messages above the reply, so your team has the context. A message.received webhook for your own system is coming soon. The full API reference is in your Chateta dashboard.
Pricing

WhatsApp packages for Sri Lanka

A flat monthly fee for the API, webhooks and inbox. Unlimited contacts on every package.

WhatsApp Starter

For a single store or clinic sending OTPs and order alerts.

€9.99 /month

≈ Rs. 3,750, charged in EUR

  • 5,000 API messages / month
  • 1 WhatsApp number
  • 1 inbox seat
  • Unlimited contacts
  • Message templates
  • Delivery and read webhooks
  • Team inbox for replies
Book an onboarding call

WhatsApp Growth

For growing businesses with a small team answering replies.

€19.99 /month

≈ Rs. 7,500, charged in EUR

  • 15,000 API messages / month
  • 2 WhatsApp numbers
  • 3 inbox seats
  • Unlimited contacts
  • Message templates
  • Delivery and read webhooks
  • Team inbox for replies
Book an onboarding call

WhatsApp Scale

For high-volume senders, multiple brands or branches.

€29.99 /month

≈ Rs. 11,250, charged in EUR

  • 30,000 API messages / month
  • 5 WhatsApp numbers
  • 5 inbox seats
  • Unlimited contacts
  • Message templates
  • Delivery and read webhooks
  • Team inbox for replies
Book an onboarding call

Meta's message fees are separate

Meta charges per template message, by category, and bills it directly to the card on your WhatsApp Business account. We add no markup. See Meta's current rates

Sign-up opens soon

We are onboarding launch customers by hand. Book a call, or request early access on Notify.lk.

For Sri Lankan (+94) WhatsApp numbers. Rupee amounts are approximate (€1 ≈ Rs. 376, September 2026); you are charged in EUR. AI replies and the website chat widget are not included. Need them? See all Chateta plans.

Free for launch customers

We set it up for you

Meta's business verification and template review are the slow part of going live on WhatsApp. Our team handles them with you, so your developers only have to swap one API call.

Book an onboarding call

Onboarding includes

  • Meta Business portfolio setup and business verification
  • Connecting your WhatsApp number and business profile
  • Writing and submitting your first message templates for approval
  • A test send from your own system before you go live
FAQ

Frequently Asked Questions

Is this the official WhatsApp Business API?

Yes. Chateta is an official Meta Tech Partner and connects directly to Meta's WhatsApp Business Platform. There is no unofficial WhatsApp Web automation involved, which is what puts numbers at risk of being banned.

Why are there two bills?

Chateta charges a fixed monthly fee for the API, webhooks and inbox. Meta charges its own fee for each template message, billed directly to the card on your WhatsApp Business account. We add no markup to Meta's fees, and Meta publishes its current rates on its pricing page.

Do I need a Facebook or Meta business account?

You need a Meta Business portfolio (formerly Business Manager), and Meta will verify your business, usually with your business registration documents. If you don't have one yet, we set it up and get it verified with you during onboarding. Your personal Facebook profile is only used to log in and is never shown to customers.

Can I keep my current number?

Yes, as long as it is a Sri Lankan (+94) number that can receive a verification SMS or voice call, landlines included. If the number is already registered in the WhatsApp or WhatsApp Business app, it has to be removed from the app before it can move to the API, so many businesses use a separate number for API messages. We'll help you choose during onboarding.

Can I keep sending SMS through Notify.lk?

Yes. Your Notify.lk account, sender IDs and SMS prices stay exactly as they are. Most businesses use both: WhatsApp for OTPs, alerts and conversations, and SMS for bulk promotions and customers without WhatsApp. Automatic SMS fallback through your own Notify.lk account is coming soon.

Who charges my card, and why in euros?

Chateta is run by Beyond Git, a company registered in the Netherlands. The monthly fee is charged in EUR to your card through Stripe, so your statement shows it as an international payment and your bank may add its own foreign currency fee. Notify.lk does not bill you for WhatsApp.

What happens when I reach my monthly limit?

API sends pause until your allowance resets on the 1st of the next month, or until you move to a bigger package. Failed messages don't count towards the limit, and replies your team sends from the inbox are not API messages. If you expect a spike, such as a festive season sale, talk to us and we'll help you size the package.

How do I know a message was delivered?

Every send returns a message ID. Chateta then posts signed webhooks to your URL as the status changes (message.sent, message.delivered, message.read and message.failed), and you can also fetch the message with GET /messages/{id}.

Can I send a message without a template?

Only inside WhatsApp's 24-hour customer service window. After a customer messages you, you have 24 hours to reply with free-form text through POST /messages/text or from the inbox. Outside that window, WhatsApp requires an approved template.

Can I add AI replies later?

Yes. Move to a Chateta Startup, Pro or Ultra plan to add AI replies from your knowledge base, the website chat widget, Messenger and email in the same inbox. Those plans have different message and contact limits, so we'll help you pick one that fits your sending volume.

Put your OTPs and order alerts on WhatsApp

Tell us what you send today and we'll help you move the right messages to WhatsApp, and keep the rest on SMS.

Book an onboarding call Early access via Notify.lk

WhatsApp by Notify.lk, powered by Chateta.