How to Send SMS for Free Using APIs

SMS remains the most reliable way to reach users instantly. These free APIs enable programmatic SMS sending for two-factor authentication, alerts, and notifications.

SMSBlast - Global SMS Delivery

Send SMS to 200+ countries with delivery receipts and scheduled sending. Supports Unicode for international characters. 100 free SMS per month.

curl -X POST https://freeapitools.dev/api/v1/sms/send \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "to": "+14155552671",
    "message": "Your verification code is 123456"
  }'

# Response:
# {
#   "id": "sms_abc123",
#   "status": "sent",
#   "segments": 1,
#   "cost": 0.00,
#   "delivered_at": null
# }

View SMSBlast docs →

Common Use Cases

• Two-factor authentication (2FA): Send verification codes
• Order confirmations: Notify customers of purchases
• Delivery updates: Real-time shipment tracking
• Appointment reminders: Reduce no-shows
• Password resets: Secure account recovery
• Critical alerts: System downtime or security issues

SMS Length and Segmentation

Standard SMS supports 160 characters. Longer messages are split into segments:

• 1-160 chars: 1 segment
• 161-306 chars: 2 segments
• 307-459 chars: 3 segments

Unicode messages (emojis, non-Latin characters) support only 70 characters per segment.

Delivery Receipts

curl "https://freeapitools.dev/api/v1/sms/status/sms_abc123"

# Response:
# {
#   "id": "sms_abc123",
#   "status": "delivered",
#   "delivered_at": "2026-01-30T14:23:45Z",
#   "error": null
# }

Best Practices

• Keep it short: Aim for under 160 characters
• Include brand name: Users should know who's texting
• Add opt-out: Include "Reply STOP to unsubscribe"
• Respect timezones: Don't send at 3 AM
• Rate limit: Don't spam users with frequent messages

Get Started

Start sending SMS in minutes:

Get Free API Key →