Many people want to add personal touches like affectionate symbols (e.g., "x" for a kiss) to messages but often forget or find it repetitive. An automated way to append customizable suffixes to messages for specific contacts could save time and ensure consistency in personal communication.

The Core Idea

One approach could involve a system that automatically adds a user-defined suffix (text, emoji, or combination) to messages sent to designated contacts. This could work as:

• A keyboard extension compatible with existing messaging apps
• A plugin for platforms like WhatsApp or iMessage
• A standalone messaging app with this as a core feature

For instance, if someone assigns "xx" to their partner, every message to that contact would end with those characters. The feature could be toggled per contact or disabled entirely when unwanted.

Implementation Strategy

A keyboard extension MVP might be the most practical starting point, as it wouldn't require users to switch messaging platforms. Core functionality could include:

• Contact-specific suffix assignment
• Customizable suffix options (with emoji support)
• Settings to control when suffixes are added

More advanced versions could incorporate scheduling (only adding suffixes at certain times) or contextual awareness (different suffixes for different situations).

Differentiation from Existing Tools

While apps like TextExpander allow text shortcuts, they require manual activation. Keyboard apps like SwiftKey predict words but don't automate personal touches. This idea focuses specifically on effortless, contact-based message customization—a niche not directly addressed by current solutions.

The concept's strength lies in its simplicity and specific use case. Success would depend on seamless integration with existing messaging habits and clear privacy protections to address concerns about message processing.