# FieldKit: A Simple Library for Complex Input Formatting

DevFeed: [FieldKit: A Simple Library for Complex Input Formatting](<https://devfeed.tech/articles/fieldkit-a-simple-library-for-complex-input-formatting-15654.md>)

Original publisher: [Read original article](<https://developer.squareup.com/blog/fieldkit-a-simple-library-for-complex-input-formatting>)

Author: Square Engineering

Published: 2015-09-09T16:10:00Z

Content type: article

Language: en

Sources: [Square Corner Blog RSS Feed](<https://devfeed.tech/sources/square-corner-blog-rss-feed.md>)

Topics: [Library](<https://devfeed.tech/topics/library.md>), [npm](<https://devfeed.tech/topics/npm.md>), [User Experience](<https://devfeed.tech/topics/user-experience.md>)

Tags: [code](<https://devfeed.tech/tags/code.md>), [engineering](<https://devfeed.tech/tags/engineering.md>), [formatting](<https://devfeed.tech/tags/formatting.md>), [library](<https://devfeed.tech/tags/library.md>), [npm](<https://devfeed.tech/tags/npm.md>), [real-time](<https://devfeed.tech/tags/real-time.md>), [user-experience](<https://devfeed.tech/tags/user-experience.md>)

## AI overview

Square's open-source FieldKit library formats text inputs in real time as users type. It includes formatters for credit card numbers, expiry dates, phone numbers, localized currency, and Social Security numbers, along with APIs for custom formatting and specialized card and expiry-date fields.

## Source excerpt

Real-time, input text field formatting as a user types.