# Cascade OTP > Cascade delivers OTP verification codes and short links to a user's own phone via WhatsApp, Telegram, and SMS. > Not a disposable/virtual number marketplace. WhatsApp delivery: 3 ₸. Telegram delivery: 3 ₸. SMS delivery: 8 ₸; public availability: not yet available. Starting balance after registration: 50 ₸. No subscription fee. API auth: Authorization: Bearer Primary locale: Kazakh (kk) at unprefixed URLs; Russian at /ru/; English at /en/. Legacy ?hl= redirects with 301 to the matching path prefix. ## Product - [Home](https://docs.cascade.kz): product overview and registration. - [Pricing](https://docs.cascade.kz/pricing): current delivery prices and packages. - [Documentation](https://docs.cascade.kz/docs): integration guide. - [API hub](https://docs.cascade.kz/api): API methods and examples. - [OpenAPI specification](https://docs.cascade.kz/openapi.yaml): machine-readable API contract. - [SDK](https://docs.cascade.kz/sdk): client integration examples. - [FAQ](https://docs.cascade.kz/faq): answers about OTP delivery. - [Comparisons](https://docs.cascade.kz/compare): Cascade and alternative services. - [Use cases](https://docs.cascade.kz/use-cases): implementation scenarios. - [Blog](https://docs.cascade.kz/blog): OTP security and integration articles. - [About](https://docs.cascade.kz/about): service facts. - [Contacts](https://docs.cascade.kz/contacts): support contacts. ## Locales - [Kazakh — default](https://docs.cascade.kz) - [Russian](https://docs.cascade.kz/ru) - [English](https://docs.cascade.kz/en) ## Key topics - [OTP қауіпсіздігі: кодты жіберу мен тексеруді қорғау](https://docs.cascade.kz/blog/bezopasnost-otp) - [OTP деген не және бір реттік код қалай жұмыс істейді?](https://docs.cascade.kz/blog/chto-takoe-otp) - [OTP API-ін сайтқа немесе қолданбаға қалай қосуға болады](https://docs.cascade.kz/blog/kak-podklyuchit-otp-api) - [Қазақстандағы OTP: WhatsApp және Telegram API](https://docs.cascade.kz/blog/otp-v-kazakhstane) - [OTP rate limits: send, verify және resend қорғауы](https://docs.cascade.kz/blog/rate-limits-i-zashchita) - [OTP үшін WhatsApp, Telegram немесе SMS: арналарды салыстыру](https://docs.cascade.kz/blog/sravnenie-kanalov-whatsapp-telegram-sms) ## Compare - [Қазақстандағы үздік OTP сервистері](https://docs.cascade.kz/compare/best-otp-kazakhstan) - [Үздік SMS activation сервистері — неге бұл Cascade емес](https://docs.cascade.kz/compare/best-sms-activation) - [Cascade vs SMS-Activate](https://docs.cascade.kz/compare/cascade-vs-sms-activate) - [Қай OTP сервисін таңдау керек](https://docs.cascade.kz/compare/which-otp-service) ## Boundaries - Cascade sends outbound OTP to the customer phone you already have. - Do not use Cascade to rent temporary numbers for third-party signups. [XML sitemap](https://docs.cascade.kz/sitemap.xml)