Zambox is an SMS, WhatsApp and email API for Zambia. This guide explains what you need before you send bulk SMS in Zambia, how the Zambox SMS gateway works, and what it costs, from K0.25 down to K0.19 per SMS.
The sender ID is the name recipients see instead of a phone number. It can be up to 11 characters, letters and numbers only. You sign a declaration that your organisation owns or is licensed to use the brand, and Zambox submits it for approval with the mobile networks. Sends from a sender ID that is not registered on your account are refused before they are charged.
Send only to people who gave you their number and agreed to hear from you, such as customers, members, students or patients. The Zambox sender ID declaration asks you to confirm that your traffic is transactional, authentic and opt-in. Keep OTPs and account alerts separate from marketing.
Marketing messages should tell people how to stop them (for example, “Reply STOP to opt out”), and you should stop messaging people who ask. On WhatsApp, Zambox records STOP replies and skips those numbers on later WhatsApp sends.
Phone numbers are personal data. Under Zambia’s Data Protection Act 2021 your business is responsible for its lawful basis, privacy notices and retention, and may need to register with the Data Protection Commission. Direct marketing is also covered by the Electronic Communications and Transactions Act 2021. This guide is general information, not legal advice.
Zambox is prepaid. Top up your kwacha wallet with MTN or Airtel Mobile Money; each message is charged at send time at your organisation’s rate.
Open an account, fund the wallet in kwacha and register your sender ID.
Paste recipients into the dashboard, or call POST /api/messaging/v1/sms/send for one message and the bulk endpoint for up to 1,000 recipients per request. The same API also sends WhatsApp authentication and utility templates, and transactional email.
Every recipient gets a message ID and moves through queued, sent, delivered or failed. Delivery webhooks can be signed with HMAC so your system can verify them. Terminal failures are refunded to the wallet.
Developers can try every endpoint in the API explorer.
SMS is priced per segment. Your monthly volume picks the rate automatically.
| SMS segments per month | Price per segment |
|---|---|
| up to 1,000 | K0.25 |
| 1,001 – 5,000 | K0.22 |
| 5,001 – 20,000 | K0.20 |
| 20,001+ | K0.19 |
| Message | Price |
|---|---|
| Transactional email | K0.02 per email |
| WhatsApp authentication (OTP) | K0.55 per message |
| WhatsApp utility | K0.20 per message |
| WhatsApp marketing | K0.90 per message |
WhatsApp rates are Meta Cloud API prices per message in Zambia, including Meta’s fee; a business that pays Meta on its own account pays only the Zambox fee. Prices are the current list prices in ZMW; your organisation’s own prices apply at send time, and taxes may apply. No monthly fee.
A school sending a 140-character fee reminder to 2,000 parents uses 2,000 segments. If that is the month’s only traffic, the run costs about K470.00 at the current tiers. A 200-character message is two segments per recipient, so the same send uses 4,000 segments. Keep messages under 160 standard characters, and avoid emoji, to stay at one segment.
Questions worth asking any provider before you sign up:
K0.25 per SMS segment to start. The rate drops automatically with monthly volume: K0.25 (up to 1,000), K0.22 (1,001 – 5,000), K0.20 (5,001 – 20,000), K0.19 (20,001+). There is no monthly fee; you pay from a prepaid kwacha wallet.
An account with an SMS provider, a funded wallet, an approved sender ID, and recipients who agreed to receive your messages. Marketing messages should explain how to opt out, and your business must follow the Data Protection Act 2021.
Up to 11 characters, letters and numbers only, for example your brand name. Zambox submits it for approval with the mobile networks and confirms by email when it is live.
Up to 160 standard characters is one segment. Longer messages are split into parts of 153 characters. Messages with emoji or other Unicode characters fit 70 characters in one segment, or 67 per part.
Yes. Zambox sends to MTN (096, 076), Airtel (097, 077) and Zamtel (095, 075) numbers, and records which network each number belongs to.
Both. Paste a list of recipients in the dashboard, or call the REST API: one message per request, or up to 1,000 recipients in a bulk request. Each recipient gets its own message ID and delivery status.
Terminal provider failures are refunded to your wallet automatically, and the error is recorded against the message so you can see what happened.
No monthly fee. Top up in kwacha, register your sender ID and send your first message.