Send unlimited permission campaigns through your business Gmail or cPanel hosting, broadcast via paired Android SIM cards, dispatch bulk WhatsApp with automatic 500-message rollover & Meta AI anti-ban protection, and integrate sub-second SMS, WhatsApp & Email OTP verification into your apps — with zero third-party per-message fees.
Whether you are a marketer dispatching thousands of campaigns or a developer securing customer logins with instant OTPs, FastSend delivers maximum performance directly through your owned hardware and mailboxes.
Route high-volume permission emails directly through your business Google Workspace, Gmail, or cPanel domain SMTP mailboxes. Eliminate expensive recurring fees from SendGrid and Mailchimp.
Pair any Android smartphone using our lightweight APK to transform your regular mobile SIM card packs (Jio, Airtel, Vi, etc.) into an automated high-speed bulk SMS dispatch server.
{{name}}, {{due_date}})Connect multiple WhatsApp numbers in 15 seconds simply by scanning a QR code with your phone. Broadcast personalized messages with automatic multi-account rollover and Meta AI anti-ban protection.
{Hello|Hi|Hey} creates unique text per recipientStop burning thousands on Twilio or MSG91 per-SMS surcharges. Generate, dispatch, and verify 4–6 digit login and transaction OTPs through your paired SIM gateway via a unified REST API.
/api/v1/otp/send and /api/v1/otp/verifyDeliver beautiful, branded one-time passcodes and account verification codes straight to user inboxes using direct SMTP handshakes, eliminating expensive transactional email vendors.
Copy-pasteable code examples for modern tech stacks. Connect your web applications, mobile apps, or backend microservices instantly.
curl -X POST "https://fastsend.csvlorg.in/api/v1/otp/send" \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"channel": "sms",
"recipient": "+919876543210",
"digits": 6,
"expiry_seconds": 300,
"message_template": "Your verification code is {{otp}}. Valid for 5 minutes."
}'
{
"status": "success",
"message": "OTP generated and dispatched successfully",
"data": {
"channel": "sms",
"recipient": "+919876543210",
"session_token": "tok_94a7e2b1c8f490",
"expires_at": "2026-10-26 12:01:56",
"expires_in_seconds": 300,
"hardware_gateway": "SIM-1 (Jio 5G)"
}
}
Pass recipient, otp_code, and session_token to verify in 1 click.
Compare total marketing & OTP costs across SendGrid, Mailchimp, and Twilio versus running on your own mailboxes and SIMs.
Compare our all-in-one architecture against fragmented third-party email, SMS, and OTP tools.
| Feature | FastSend | SendGrid | Twilio / MSG91 | Mailchimp |
|---|---|---|---|---|
| Bulk Email Dispatch Fees | ₹0 / email | ₹0.08 per email | N/A | Tier Surcharges |
| Bulk SMS Delivery via SIM | Included (Android APK) | Not Available | ₹0.35 per SMS | Not Available |
| Developer SMS OTP API | Native REST API | Not Available | Expensive Pay-Per-OTP | Not Available |
| Developer Email OTP API | Native REST API | Generic SMTP only | Not Available | Not Available |
| Multi-Mailbox Auto Rotation | Automatic Round-Robin | Single Domain | N/A | Single Domain |
| Credential Vault Security | AES-256-CBC Vault | Third-Party Cloud | Third-Party Cloud | Third-Party Cloud |
Unlock Bulk Email Marketing, Bulk SMS SIM Hub, and Developer OTP APIs with a single subscription.
Testing bulk campaigns & integrating developer OTP APIs.
Growing companies, agencies, e-commerce, and SaaS platforms.
High-volume outreach agencies, call centers, and multi-domain platforms.
Join businesses and developers who stopped paying third-party API surcharges. Deploy FastSend in under 60 seconds.