SMS remains the most direct channel for reaching your customers: it is opened at a rate of ~98%, and most of the time within the first few minutes of delivery. Bulk SMS sending lets a business send the same (or a personalized) message to thousands of recipients at once, from a single platform. In this guide we look at what it is, how it works, what it costs and how to get started the right way.
What is bulk SMS sending?
Bulk SMS sending (or bulk SMS) is the simultaneous delivery of text messages to a large list of recipients through a web platform or API, not from a mobile phone. It is used for promotional campaigns, notifications, appointment reminders, verification codes (OTP) and order updates.
Unlike sending from a phone, a professional platform offers a branded sender name (Sender ID), delivery reports, personalization, scheduling and consent management.
How does it work?
The process is simple and follows 4 steps:
- Contact list: import your contacts (CSV/Excel) or collect them with popup forms and keywords, always with consent.
- Message: write the text, add personalization (e.g. the first name) and select your Sender ID.
- Sending: send immediately or schedule the campaign for a specific time.
- Reports: track deliveries, failures and replies in real time.
With iSend's SMS & Viber campaigns all of this happens in one place, and with automations you can send messages automatically (e.g. birthday wishes or reminders).
Why does SMS marketing work?
- Open rate of ~98%: no other channel comes close to this read rate.
- Immediacy: most SMS messages are read within a few minutes.
- Universal reach: it works on every mobile phone, with no app or internet required.
- High ROI: low cost per message with measurable results.
Bulk SMS sending & GDPR: what to watch out for
Legality is fundamental. For promotional SMS you need the recipient's explicit consent (opt-in), with an easy way to unsubscribe (opt-out). The basic rules:
- Collect consent for a clear purpose and keep proof (timestamp, IP, consent text).
- Respect quiet hours: avoid sending late at night or early in the morning.
- Always provide a way to opt out (e.g. the word STOP or an unsubscribe link).
- Keep your blocklists up to date so you never send to anyone who has opted out.
The iSend platform includes consent management, STOP keywords, blocklists and quiet hours so you are compliant by default.
How much does bulk SMS sending cost?
The cost depends on volume. iSend bills through a monthly subscription to credit packages (e.g. Basic, Professional, Enterprise), where unused credits roll over to the next month. The higher the volume, the lower the cost per message. See the full packages & pricing.
Best practices for effective campaigns
- Short & clear: an SMS has 160 characters. Say what matters and include a clear call-to-action.
- Personalization: the recipient's name increases engagement.
- Right timing: send at suitable hours, not in bulk without a reason.
- Segmentation: target groups with a relevant message instead of one message to everyone.
- Measure: track delivery & conversions and optimize.
For online stores, a powerful use case is recovering abandoned carts with automatic SMS. And when you need images or buttons, Viber is the ideal complement to SMS.
Conclusion
Bulk SMS sending is one of the most cost-effective marketing channels for Greek businesses: immediate, with a huge open rate and measurable ROI. With the right platform, GDPR compliance and a little planning, you can get started in minutes.