sinch-verification-api

Name: sinch-verification-api
Availability: InStock
Author: Sinch

Verify phone numbers via SMS, flashcall, call, carrier data, or WhatsApp.

9|4|Updated Jan 29, 2026

Search Tags:#verification #whatsapp #webhooks #otp #sms #two-factor #flashcall

Ready to run

npx skills add https://github.com/sinch/skills --skill sinch-verification-api

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: sinch-verification-api
Source: https://github.com/sinch/skills/tree/main/skills/sinch-verification-api
Command: npx skills add https://github.com/sinch/skills --skill sinch-verification-api

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

This Skill provides a secure, standardized way to verify phone numbers and deliver one-time passwords or carrier-level attestations to confirm number ownership and reduce account fraud.

Core Features & Use Cases

Multiple verification methods: SMS OTP, Flashcall (missed call CLI), Phone Call (spoken OTP), carrier Data (seamless), and WhatsApp OTP.
SDK and direct HTTP guidance: Instructions and references for using Sinch SDKs or direct API calls with application key and secret authentication.
Operational patterns and safety: Start-report-status flows, reporting by verification id, signed callback webhooks, rate-limit guidance, and signing best practices.
Use Cases: User registration and onboarding, two-factor authentication, passwordless login, account recovery, and anti-fraud verification flows.

Quick Start

Start an SMS verification for +12025550134 using your application key and secret and return the verification id.

Frequently Asked Questions about sinch-verification-api

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I implement phone verification via SMS or WhatsApp for user registration?▼

Phone verification for user registration is implemented by starting an SMS or WhatsApp verification, reporting the one-time password by verification id or number, and querying the verification status using your application key and secret.

What is the best way to add two-factor authentication using phone calls or missed calls?▼

Two-factor authentication is delivered via phone call spoken OTP or flashcall missed call CLI verification, utilizing the start-report-status flow to confirm number ownership and secure user logins.

Can I use signed callback webhooks to receive verification status updates?▼

Signed callback webhooks are supported to securely receive verification status updates, ensuring payload authenticity through signing best practices alongside rate-limit guidance for operational safety.

Does this support seamless carrier data verification for passwordless login?▼

Seamless carrier data verification is supported for passwordless login, providing carrier-level attestations to confirm number ownership without requiring manual one-time password entry from the user.

How do I authenticate API requests for starting verifications and reporting codes?▼

API requests for starting verifications and reporting codes are authenticated using your application key and secret, either through Sinch SDKs or direct HTTP calls for secure access.

What verification methods work for anti-fraud flows in mobile and web applications?▼

Anti-fraud verification flows for mobile and web applications are supported through SMS OTP, flashcall, phone call, seamless carrier data, and WhatsApp methods to reduce account fraud.