feature request: Improve SMS Sign-in: Auto-Detect Country Code via Regex Rules

[eygsoft]

What problem did you meet?

1. Currently, users can select any country code, but some apps need to restrict them (e.g., only +86 for China).

2. When browsers auto-fill a phone number (e.g., +8613912345678), users must: ◦ Delete +86 from the input ◦ Manually select +86 from the dropdown

Describe what you'd like Logto to have

• Allow admin-configurable regex rules for each country code. • When a user types/pastes a phone number:

1. The system checks if the input matches any configured regex (e.g., ^+86(1[3-9]\d{9})$ for China).
2. If matched, automatically select the correct country code and trim the prefix from the input.
3. If multiple regexes match (e.g., +1 for US/Canada), apply the first matched rule in priority order.

These changes would greatly improve usability, especially for applications targeting specific regions. Thank you for your consideration!

[Rany0101]

Thanks for sharing this suggestion! We've added your feature request to our public roadmap where it is open for voting. Country code restrictions for phone input / Smart country code detection