DualPin — smart-correcting Shuangpin keyboard for iOS

An iOS Shuangpin keyboard with smart correction, symbol swipes, and WebDAV dictionary sync

Problem

Gboard is the only iOS keyboard with decent Shuangpin smart correction, but it has clear pain points: no symbol input by swiping letter keys, no semicolon key which makes Microsoft Shuangpin awkward, and memorized phrases mysteriously vanish every few months; WeChat's keyboard correction is too weak to use.

Solution

An iOS Shuangpin keyboard focused on smart correction for mixed Chinese-English blind typing, symbol input via letter-key swipes, a preserved semicolon key for Microsoft Shuangpin and similar layouts, and rime-format dictionary sync over WebDAV with desktop input methods, with no network access beyond sync.

Users

iOS users who type in Shuangpin and care about speed and privacy, especially Microsoft Shuangpin users who need cross-device dictionary sync.

MVP

System keyboard extension with smart-correcting Shuangpin; symbol input on letter-key swipe; preserved semicolon key; rime dictionary import and WebDAV sync; no network requests beyond WebDAV.

Revenue

App Store one-time purchase or low-cost annual subscription; dictionary sync as a paid feature while basic typing stays free.

Why now

Big input-method vendors under-serve the Shuangpin niche, and iOS keyboard extension APIs are now capable enough for an indie developer to build a differentiated product.