---
title: What is the difference between source variable and static text in Fallback mapping?
description: "**Source variable** copies a dynamic value from the first channel in your sequence (e.g. the OTP sent on SMS). **Static text** inserts the same fixed words on every send, regardless of the message content. ## Source variable (recommended for OTPs and personal data)…"
url: "https://www.smsgatewaycenter.com/blog/kb/what-is-the-difference-between-source-variable-and-static-text-in-fallback-mapping/"
updated: "2026-06-29"
category: "Users / Multi-Channel Fallback"
---

# What is the difference between source variable and static text in Fallback mapping?

**Source variable** copies a dynamic value from the first channel in your sequence (e.g. the OTP sent on SMS). **Static text** inserts the same fixed words on every send, regardless of the message content.

## Source variable (recommended for OTPs and personal data)

Use when the WhatsApp or RCS step must show the *same* value the customer received on SMS.

**Example:** SMS variable holding OTP `482910` → map WhatsApp `{{1}}` to that source variable → WhatsApp shows `482910`.

## Static text (recommended for disclaimers and fixed lines)

Use when the target channel should always include identical wording.

**Example:** RCS footer always says “Do not share this code with anyone.” regardless of OTP value.

## Common mistakes

- Leaving a target variable unmapped → save fails.
- Using static text for OTP → every customer gets the same wrong code.
- Not re-mapping after changing templates → placeholders may break.

### More Related Articles

- [How do I preview fallback messages before going live?](https://www.smsgatewaycenter.com/blog/kb/how-do-i-preview-fallback-messages-before-going-live/)
- [Can I use Fallback for promotional bulk campaigns?](https://www.smsgatewaycenter.com/blog/kb/can-i-use-fallback-for-promotional-bulk-campaigns/)
- [Why is my fallback flow not trying the next channel?](https://www.smsgatewaycenter.com/blog/kb/why-is-my-fallback-flow-not-trying-the-next-channel/)

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