Diction vs Willow
Both are iOS voice keyboards. The difference is where your audio goes and what it costs.
The core difference
Willow is primarily cloud-based. Your audio gets sent to their servers for transcription. The iOS app has a limited offline fallback, but it's not a full on-device mode. There is no way to self-host.
Diction lets you choose. On-device mode runs entirely on your iPhone with zero network requests. Self-hosted mode sends audio to a server you control. Cloud is available if you want it, but never required.
Side-by-side
| Diction | Willow | |
|---|---|---|
| On-device (fully offline) | Yes | Limited fallback |
| Self-hosted | Yes | No |
| Cloud mode | Yes (optional) | Required |
| iOS keyboard | Yes | Yes |
| Custom dictionary | Yes (My Words) | No |
| Per-app tone presets | Yes | No |
| Open-source server | Yes | No |
| End-to-end text encryption | AES-256 + X25519 | No |
| Free tier | On-device is free, no limits | 2,000 words/week |
| Paid plan | Subscription for cloud | $12-15/month |
Privacy
Willow says they don't collect transcriptions by default. But cloud-only means your audio always leaves your device. You're trusting their infrastructure and their policies.
With Diction on-device, there is no server involved. Audio is processed locally and discarded. Nothing is transmitted. In self-hosted mode, audio goes to your server only. Either way, transcriptions are encrypted with AES-256-GCM using X25519 key exchange before they travel anywhere.
Pricing
Willow caps the free tier at 2,000 words per week. After that, it's $12-15/month for unlimited.
Diction's on-device mode is free with no word limits, no weekly caps, no restrictions. Self-hosting is free if you run a server. The Diction One cloud subscription is only needed if you want hosted transcription.
Why Diction
If your audio staying on your device matters to you, Diction is the clear choice. Willow's offline fallback is limited and there's no path to self-hosting. If you work in healthcare, legal, or any environment where audio can't leave your network, cloud-only is a non-starter.
Diction's custom dictionary means names and jargon come through correctly, and per-app tone presets let your emails sound professional while your messages stay casual. Willow has neither.
If you don't want to pay for dictation, Diction's on-device mode has no caps. Willow's free tier runs out after a few emails.
Diction is available on the App Store. The server is open source at github.com/omachala/diction.