SMS & OTP Simulator

The SMS Simulator gives your team a realistic view of how text messages appear on mobile devices (iOS and Android) without having to route SMS to real phone numbers during development.

Automatic OTP & 2FA Extraction

Sinkbox parses incoming SMS payloads to detect numeric verification codes (4 to 8 digits) and displays a prominent copy badge right at the top of the preview.

• One-Click Copy: Quickly copy the authentication code into your clipboard with a single click or keyboard action.
• Automated Test Ready: The same OTP extraction logic is available through the Sinkbox REST API for end-to-end authentication tests.

Segment & Character Encoding Metrics

Ensure your automated SMS campaigns remain cost-efficient and within provider segment thresholds:

• GSM-7 vs Unicode (UCS-2): Sinkbox checks each character in your message. Standard GSM-7 messages allow up to 160 characters per segment. If special Unicode emojis or characters are present, the encoding switches to UCS-2 (70 characters per segment).
• Multipart Concatenation Calculation: Calculates the exact billing segment count for multi-part messages (153 characters per GSM-7 segment or 67 characters per UCS-2 segment).

OS Theme & Presentation

Toggle between iOS (Apple iMessage bubble) and Android (Google Material message) styles, and test light vs. dark mode themes.