On-Device OCR & Expiry Detection
When you scan a passport, ID card, or insurance policy, UnderKey uses Google ML Kit Text Recognition to read the expiry date and suggest it automatically. The entire process happens on your device — your documents and the recognized text are never uploaded or sent to UnderKey or Google.
How it works
- You scan or import a document using UnderKey's document scanner or photo import.
- Google ML Kit processes the image entirely on your device to recognize text, including dates, names, and document numbers.
- UnderKey looks for date patterns that match common expiry date formats (e.g., "Expiry: 05/03/2030", "Valid until 2030-03-05").
- If an expiry date is found, UnderKey suggests it so you can accept, edit, or skip it.
- The expiry date is stored encrypted alongside the document and used to set a local reminder before it expires.
At no point does UnderKey upload your document or the recognized text. Google ML Kit runs on your device, and the text recognition data never leaves it.
What third parties are involved
On iOS
Google ML Kit is bundled inside the app. When you scan a document, the text recognition runs on-device using the ML Kit framework included in the app binary. No downloads, no network requests, no data leaving your phone.
On Android
The first time you use the OCR feature, Google Play Services may download a text recognition component or model via a one-time system-level download. Once downloaded, all text recognition runs on-device. This download is managed by Google Play Services, not UnderKey.
After the initial download, the OCR feature works offline and does not require an internet connection.
What documents does it work on?
The OCR feature can recognize text on any document, but expiry date detection works best on:
- Passports (expiry date is printed clearly on the photo page and encoded in the MRZ).
- National ID cards and driver's licences (expiry dates are usually in a consistent format).
- Insurance cards and policy documents.
- Vehicle registration and MOT/TÜV certificates.
- Visas and residence permits.
For documents where the expiry date isn't clearly labelled (e.g., handwritten notes, receipts), the OCR may not detect it automatically. You can always enter it manually.
What if the suggested date is wrong?
OCR isn't perfect. Blurry photos, poor lighting, or unusual date formats can confuse the text recognition. If UnderKey suggests the wrong date — or no date at all — you can:
- Edit the date manually before saving it.
- Skip the expiry date and add it later if you prefer.
- Re-scan the document with better lighting or a flatter surface.
Always double-check the suggested expiry date against the document to make sure it's correct before setting a reminder.
Can you disable OCR?
Yes. The OCR feature is optional. If you prefer to enter expiry dates manually, or if you don't want to use Google ML Kit at all, you can skip the OCR step and type the date yourself.
Privacy and data practices
- UnderKey does not upload your documents or the recognized text. Everything happens on your device.
- Google ML Kit does not send your documents or recognized text to Google. The text recognition runs entirely on-device. For Google ML Kit's own data practices, see Google's ML Kit Terms.
- The recognized text is not logged or cached outside the app. Once UnderKey extracts the expiry date and you save the document, the recognized text is discarded.
Limits
- OCR accuracy depends on image quality. Blurry, dark, or angled photos reduce accuracy. Use the document scanner with good lighting for best results.
- Handwritten dates are harder to recognize. ML Kit is trained on printed text and may struggle with handwriting.
- The feature requires Google Play Services on Android. If you've removed or disabled Play Services, the OCR feature won't work on Android devices.
Related features
- Document scanner — how to capture clear scans for OCR
- Expiry reminders — how reminders work once the date is set