How many minimum SMS units are required for an API SMS?

The minimum SMS units required for sending an API SMS on Text.lk depend on the message length, encoding and firewall rules.

How many minimum SMS units are required for an API SMS?

The minimum SMS units depend on your message length and encoding:

• 1 SMS unit is used if your message fits within:
  • 160 characters (GSM-7 encoding — standard English & symbols)
  • 70 characters (Unicode/UCS-2 encoding — includes emojis and non-Latin scripts)

If your message is longer, it’s split into multiple parts:

• GSM-7: 153 characters per additional part
• UCS-2: 67 characters per additional part

⚡ Tip: Keep messages short to stay within 1 SMS unit and save costs.

Firewall Rules & Deliverability Tips

🔒 Extra: SMS deliverability tips

• Always send full, meaningful messages — e.g. Your SuperApp OTP is: 889900. Do not share with anyone.
• Avoid very short, generic text like OTP 889900
• Include your brand/app name
• Use proper grammar and avoid sending the exact same text repeatedly

SMS firewalls are smart — they detect spam, patterns, and meaningless messages.

✅ Send full, meaningful messages, especially for OTPs.

Example:

Your SuperApp OTP is: 889900. Do not share with anyone.

❌ Avoid vague or robotic text:

OTP 889900

Short, repeated or generic content can be blocked or delayed by SMS firewalls.

Best Practice

• Always include brand/app name.
• Avoid sending the exact same message repeatedly.
• Use proper formatting and grammar.