A native macOS input method that predicts what you're typing — and what you'll type next. It shows a floating candidate bar below your cursor with word completions, spelling corrections, and next-word suggestions, all running locally with no network calls.
Built with Swift 6 and InputMethodKit. Next-word predictions are powered by KenLM n-gram language models, integrated through an Objective-C++ bridge.
- Word completions & spell correction as you type, powered by macOS's built-in spell checker
- Next-word predictions after committing a word — chain predictions by pressing Space repeatedly
- Fully offline — all predictions run locally using bundled language models, no data leaves your machine
- Expandable candidate grid — starts as a single row, expands into a navigable multi-row grid with lazy loading
- Per-app input source switching — automatically switch keyboard layouts when you focus different apps
- Themeable candidate window — customize colors, opacity, grid size, and border through the Settings UI
- Menu bar integration — shows the active language code; click to switch languages or open Settings
- Multiple languages — English and German included, with a protocol-based architecture for adding more
macOS 13.0 or later. Xcode required only if building from source.
Download the latest .pkg from Releases and double-click to install. The app is ad-hoc signed and not notarized, so you'll need to right-click → Open the installer on first launch to bypass Gatekeeper.
xcodebuild -scheme SwiftType -configuration Debug buildA Debug build automatically installs to ~/Library/Input Methods/.
- Open System Settings → Keyboard → Input Sources → Edit → +
- Select SwiftType
- Click Add
- Switch to SwiftType from the input source menu in the menu bar
Switch to SwiftType, open any text field, and start typing. The candidate bar appears below your cursor.
| Key | Action |
|---|---|
1–6 |
Commit the prediction in that column |
Space |
Commit selected prediction + show next-word suggestions |
Return |
Commit current selection |
Escape |
Commit raw text and dismiss |
The candidate bar starts collapsed (one row). Press ↓ to expand into a multi-row grid.
| Key | Action |
|---|---|
↓ |
Expand grid / move down |
↑ |
Move up / collapse at top |
Tab / → |
Cycle column right |
← |
Cycle column left |
Number keys always target the active row.
Open Settings from the menu bar icon.
| Pane | What it does |
|---|---|
| General | Toggle next-word suggestions on/off |
| Keyboards | Set up per-app input source switching — assign a keyboard layout to an app, and SwiftType switches automatically on focus |
| Languages | Add, remove, or reorder prediction languages. Pin a language or set to Auto (follows the system keyboard) |
| Customization | Adjust candidate bar appearance — 7 color options, opacity, column count (4–6), row count (3–5) |
| About | Shows the installed version |
Reset all settings: defaults delete com.matthew.inputmethod.SwiftType
Keystroke
→ SpellCheckPredictor (macOS spell checker → corrections + completions)
→ CandidateWindow (floating grid below cursor)
Word committed via Space
→ KenLMPredictor (n-gram model → top-N next words)
→ CandidateWindow (next-word mode, no literal slot)
SpellCheckPredictor wraps NSSpellChecker to produce spelling corrections, prefix completions, and fuzzy guesses — all synchronous, no network calls.
KenLMPredictor scores every word in its vocabulary against the recent typing context using a 5-gram language model, then applies truecasing to restore proper capitalization. The models are trained on 1 million news sentences from the Leipzig Corpora Collection.
Language models work best on lowercase text, but predictions need proper capitalization — especially for German, where all nouns are capitalized. SwiftType solves this by training on lowercased text for optimal statistics, then applying a separate truecase map at prediction time ("haus" → "Haus", "germany" → "Germany").
macOS → IMKServer → InputController
├── KeyHandler — language-specific key dispatch
├── InputStrategy — prediction provider
│ ├── SpellCheckPredictor (completions)
│ └── KenLMPredictor (next-word, via C++ bridge)
├── TypingRules — language-specific character sets
└── CandidateWindow — floating grid UI
All three extension points — KeyHandler, InputStrategy, and TypingRules — are protocols. Adding a new language means writing conformers and registering them in LanguageDescriptor, with no changes to the core input controller.
The entire app is @MainActor-isolated under Swift 6 strict concurrency with zero warnings and zero unsafe annotations. InputMethodKit delivers all callbacks on the main thread, so rather than fighting that constraint, the codebase leans into it — proving thread safety to the compiler with no async/await and no background threads.
xcodebuild -scheme SwiftTypeTests -configuration Debug test1,005 tests covering input state, grid navigation, key routing, spell-check predictions, KenLM predictions, theme system, settings persistence, typing rules, language management, and candidate window behavior.
SwiftType/
├── App/ App delegate, managers, menu bar, input source switching
├── Input/ Input controller, key handling, state, strategies
├── Prediction/ SpellCheckPredictor, KenLMPredictor, Obj-C++ bridge
├── Rules/ TypingRules protocol, language descriptors, English/German
├── UI/ Candidate window, settings panes, theme system
├── Tests/ 1,005 tests across all subsystems
├── Resources/ KenLM binary models + truecase maps (~164 MB)
├── Frameworks/ kenlm.xcframework (static C++ libs)
└── scripts/ KenLM model training, release packaging
./scripts/release/release.sh # auto-versioned (UTC timestamp)
./scripts/release/release.sh 1.2.0 # explicit versionProduces dist/SwiftType-<version>.pkg — a flat installer that copies the app to ~/Library/Input Methods/ and creates a /Applications/SwiftType.app symlink.
| Problem | Fix |
|---|---|
| SwiftType not in Input Sources | Rebuild to trigger auto-install, then check System Settings → Keyboard |
| Old binary after rebuild | killall SwiftType; touch ~/Library/Input\ Methods/ — or log out and back in |
| Duplicate entries | sudo rm -rf /Library/Input\ Methods/SwiftType.app then re-login |
| Gatekeeper error | Right-click → Open, or run xattr -dr com.apple.quarantine ~/Library/Input\ Methods/SwiftType.app |
