# Channel elements overview Channel elements allow you to integrate different communication methods directly into customer journeys. ### Push notifications Send personalized push messages to engage users in real time. Configure delivery timing, apply vouchers, and use frequency controls to optimize message performance. ### Multi-Armed Bandit Automatically send the best-performing push variant in journeys using real-time open rates, without manual A/B testing. ### Email Send emails with tailored content, run A/B subject line tests, manage sender details, enable BCC, apply frequency limits, and integrate voucher codes. ### In-app messages Show rich-media messages directly inside the app. Ideal for onboarding, promotions, announcements, or contextual guidance when users are active in the app. ### SMS Send short, timely messages via SMS for critical updates, confirmations, reminders, or to reach users not active in your app. ### WhatsApp Use pre-approved templates or custom replies to engage users with WhatsApp messaging. ### Viber Send Viber messages using a Rakuten-approved template or freeform text, with independent pricing and message type controls. ### Telegram Send plain text messages to users who started your bot, with optional vouchers and journey statistics. ### LINE Engage users with LINE messages using presets or free-form text. Include vouchers and configure delivery-based flow branching. ### Kakao Send approved Kakao messages via Customer Journey using Kakao templates with dynamic variables and optional vouchers. ### Data to app > Developer support required to implement this feature. Send silent pushes or JSON data that triggers in-app actions such as syncing, unlocking features, or updating content. Ideal for background updates, beta testing, and feature rollouts. ### Webhook The **Webhook** element sends journey data to external systems like analytics platforms, CRM tools, or messaging services. ## Omnichannel campaigns Combine multiple channels in one journey to reach users through their preferred touchpoints and engage those unavailable on one channel via another. This ensures consistent communication, improves message visibility, and increases the effectiveness of onboarding, re-engagement, or promotional campaigns.