SMS via Czech operators: O2, T-Mobile and Vodafone without compromise

The Czech SMS market is governed by three operators — O2 Czech Republic, T-Mobile Czech Republic and Vodafone Czech Republic — under the Czech Telecommunication Office (ČTÚ). 4notify carries a direct connection to each, so transactional SMS leaves with no aggregator margin, a local alphanumeric sender ID, and a full delivery trace inside the dashboard.

Problem

Most international platforms route Czech SMS via a European aggregator, costing you the alphanumeric sender ID (recipients see only an international number) and dropping delivery below 92%. Meanwhile ČTÚ requires the provider to honour STOP/HELP keywords, record consent and (for 90xxx premium-rate) display the price in CZK including VAT.

Legal framework

Vyhláška ČTÚ 117/2007 Sb.

Technical and operational conditions for electronic communications — defines sender ID rules, delivery time windows and mandatory STOP/HELP responses.

§ 7 zákona č. 480/2004 Sb. (ZSO)

Commercial messages require prior consent; transactional SMS (order confirmations, OTP, delivery) are exempt but opt-out must still work.

Premium-rate 90xxx — ČTÚ opatření obecné povahy č. OOP/9/10

Premium SMS must include the exact price in CZK including VAT; operators must block premium access on customer request.

Architecture

Direct connection, no aggregator

4notify holds an A2P contract with each of the three operators. SMS travels straight to the operator SMSC with no intermediate hop.

Alphanumeric sender ID

Up to 11 characters (e.g. „YourBrand“), registered once. ČTÚ approves within 1–3 working days.

STOP/HELP automation

A STOP reply via the platform immediately unsubscribes the recipient from this campaign and globally; HELP returns customer-service contact.

Status callback

Each SMS triggers a signed webhook with DELIVERED / FAILED / REJECTED status and reason (e.g. “number ported to another operator”).

Code

bash
curl -X POST https://api.4notify.net/v1/dispatch \
  -H "Authorization: Bearer $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "channel": "sms",
    "sender": "VasFirma",
    "recipient": "+420777123456",
    "body": "Vase objednavka 2026-CZ-0481 je pripravena k vyzvednuti. Otevreno do 19:00.",
    "metadata": { "campaign": "pickup_ready", "country": "cz" }
  }'

Sample message

SMS

YourBrand: Order 2026-CZ-0481 is ready for pickup at Vodičkova 28, Prague 1. Open until 19:00. STOP to unsubscribe.

Before launch

Register the alphanumeric sender ID with ČTÚ
Configure STOP/HELP keywords in the dashboard
Test delivery into all three networks (O2 / T-Mobile / Vodafone)
Wire status callback into your internal system
If using 90xxx: confirm price-in-text requirement is met
Approve GDPR opt-in record (see Kapitola 03)

What 4notify does differently

Only provider with a direct connection to all three Czech operators and a registered alphanumeric sender ID — no aggregator margin, no UTF mangling.

FAQ

What is the average delivery latency in CZ?

P50 latency from dispatch to operator ACK is 1.8 s on O2, 2.1 s on T-Mobile, 2.4 s on Vodafone. Statistics are refreshed monthly.

What happens when a number is ported between operators?

We HLR-check every dispatch — if the number has been ported, we route to the new operator. Billing follows the contracted rate for that channel.

Can we send SMS to Slovakia from the same account?

Yes. The SK channel is independent (Slovak Telekom / O2 SK / 4ka) with its own connection; same API key, same dashboard, just a different sender ID and price list.