# Cascade OTP

> Cascade delivers OTP verification codes and short links to a phone number the customer already has, via WhatsApp, Telegram, and SMS.
> Not a disposable or virtual-number marketplace.

WhatsApp delivery: 3 credits per successful send.
Telegram delivery: 3 credits per successful send.
SMS delivery: 8 credits per successful send; public availability: not yet available.
Starting balance after registration: 1000 credits.
No subscription fee.
API auth: Authorization: Bearer <token>
API base URL: https://cascade.kz/api
Send OTP: POST /api/otp/send
Verify OTP: POST /api/otp/verify
Default locale is Kazakh (kk) at unprefixed URLs. Russian lives at /ru/. English lives at /en/. Legacy ?hl= redirects with 301 to the matching path prefix.
Cascade sends outbound OTP to the customer phone you already have.
Do not use Cascade to rent temporary numbers for third-party signups.

## Docs
- [Home](https://cascade.kz/en): product overview and registration
- [Documentation](https://cascade.kz/en/docs): integration guide
- [API](https://cascade.kz/en/api): API methods and examples
- [OpenAPI specification](https://cascade.kz/openapi.yaml): machine-readable API contract
- [Integration guide (Markdown)](https://cascade.kz/cascade-otp-integration.md): downloadable Markdown integration notes for agents

## Product
- [Pricing](https://cascade.kz/en/pricing): current delivery prices and packages
- [SDK](https://cascade.kz/en/sdk): client integration examples
- [FAQ](https://cascade.kz/en/faq): answers about OTP delivery
- [Compare](https://cascade.kz/en/compare): Cascade and alternative services
- [Use cases](https://cascade.kz/en/use-cases): implementation scenarios
- [Blog](https://cascade.kz/en/blog): OTP security and integration articles
- [About](https://cascade.kz/en/about): service facts
- [Contacts](https://cascade.kz/en/contacts): support contacts

## Locales
- [Қазақша](https://cascade.kz): Kazakh site — default unprefixed URLs
- [Русский](https://cascade.kz/ru): Russian site
- [English](https://cascade.kz/en): English site
- [Kazakh llms.txt](https://cascade.kz/kk/llms.txt): Kazakh llms.txt with unprefixed URLs
- [Russian llms.txt](https://cascade.kz/ru/llms.txt): Russian llms.txt with /ru/ URLs
- [English llms.txt](https://cascade.kz/en/llms.txt): English llms.txt with /en/ URLs

## Optional
- [OTP security: protect code delivery and verification](https://cascade.kz/en/blog/bezopasnost-otp)
- [What is OTP and how does a one-time code work?](https://cascade.kz/en/blog/chto-takoe-otp)
- [How to integrate an OTP API into a website or app](https://cascade.kz/en/blog/kak-podklyuchit-otp-api)
- [OTP in Kazakhstan: WhatsApp and Telegram API](https://cascade.kz/en/blog/otp-v-kazakhstane)
- [OTP rate limits: protect send, verify, and resend](https://cascade.kz/en/blog/rate-limits-i-zashchita)
- [WhatsApp, Telegram, or SMS for OTP: channel comparison](https://cascade.kz/en/blog/sravnenie-kanalov-whatsapp-telegram-sms)
- [Best OTP services in Kazakhstan](https://cascade.kz/en/compare/best-otp-kazakhstan)
- [Best SMS activation services — why this is not Cascade](https://cascade.kz/en/compare/best-sms-activation)
- [Cascade vs SMS-Activate](https://cascade.kz/en/compare/cascade-vs-sms-activate)
- [Which OTP service to choose](https://cascade.kz/en/compare/which-otp-service)
- [XML sitemap](https://cascade.kz/sitemap.xml): full indexable URL list