Alert21
Alert21: A pay-as-you-go SMS API for OTPs, service alerts and delivery tracking. Ranked #44 of 75 in Transactional SMS Software by our editors (5.2/10); pricing: Paid; best for india-focused teams needing template-based OTP SMS.
At a glance
- Editor score5.2 / 10
- PricingPaid
- Best forIndia-focused teams needing template-based OTP SMS
- Pay-as-you-goYes
- Facts checked24 Sep 2026
Where it wins
- Maps DLT templates, sender IDs and Principal Entities
- Reports delivery lifecycle states through receipts and signed webhooks
- Supports Unicode, regional-language, bulk and scheduled SMS
Where it doesn't
- No monthly message quota is stated
- SMS rates vary by destination, route, encoding, segments, volume and taxes
- Two-way messaging is not specified
Our verdict on Alert21
Alert21 is a cloud-based SMS service from Scriza Private Limited, delivered through a web interface and REST API. It is designed for businesses sending transactional and service messages in India, including OTPs, operational alerts and lifecycle receipts. Small, mid-market and enterprise teams can use approved DLT templates, sender details and Principal Entity mappings to submit messages. Unicode and regional-language SMS extend its use to localized communication.
The API’s operational controls are a notable strength for application teams. Delivery receipts use normalized lifecycle states, while signed HTTP webhooks can report message events to connected systems. Idempotency, rate limits, request IDs, usage logs and reporting help teams manage requests and follow message outcomes. Bulk and scheduled sending cover campaigns and timed notifications, alongside transactional traffic. These capabilities make Alert21 a fit for teams that want SMS integrated into application workflows rather than a standalone messaging tool.
Pricing is pay-as-you-go with a prepaid balance in Indian Rupees, and volume discounts apply as sending scales. According to the published pricing details, rates depend on destination, route, encoding, segment count, volume and taxes, so teams should account for those variables when estimating spend. Support channels include email, phone and documentation; support is not available 24/7. The stated compliance credential is ISO 27001. Choose Alert21 if DLT-aware OTP and service messaging, delivery tracking and API controls match your needs. Teams that require confirmed two-way messaging or a predictable monthly quota should compare alternatives before committing.
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Alert21 pricing
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Alert21 fact sheet
| Free plan | Not verified |
|---|---|
| Paid from | Not verified |
| Pay-as-you-go | Yes |
| SMS API | Yes |
| Delivery status | Yes |
| Webhooks | Yes |
| Two-way messaging | Not verified |
| Monthly message limit | Not verified |
| Deployment | Cloud |
| Platforms | Web |
| Compliance & security | ISO 27001 |
| Support | Email, Phone, Docs |
| Built for | Small business, Mid-market, Enterprise (editorial estimate) |
| Pricing | Paid (source) |
| Website | alert21.in |
| Facts checked | 24 Sep 2026 |
Alternatives to Alert21
- Twilio Programmable MessagingA broad programmable messaging stack with usage-based pricing and developer-oriented controls.9.4
- AWS End User Messaging SMSA pay-as-you-go SMS API for AWS teams sending monitored global transactions.9.3
- Bandwidth SMS APIA usage-priced API for high-throughput, two-way U.S. SMS and MMS workflows.9.2
See all Alert21 alternatives →
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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
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