Why does Silktide test with an iPhone 5?
Silktide's automated mobile checks run on a simulated iPhone 5 (320 CSS pixels wide). That is deliberate. It is not the phone we use to show what your site looks like to customers today.
Testing vs presentation
| What you see | Device | Why |
|---|---|---|
| Accessibility and mobile checks | iPhone 5 (320px) | Matches the WCAG reflow width |
| Home page overview screenshot | iPhone 16 | A modern phone for display |
| Inspector device presets | iPhone 5, X, 14, 16, and others | You choose what to preview |
So if a report still mentions an iPhone 5 in a check finding, that is the test viewport. If the website overview shows a modern phone frame, that is presentation.
Why 320 pixels
success criterion 1.4.10 Reflow () requires content to fit a 320 CSS pixel wide viewport without forcing the reader to scroll both horizontally and vertically (with limited exceptions for things like maps and data tables).
320 CSS pixels is also what you get when someone on a larger screen zooms to around 400%. Testing at that width catches layout that breaks for:
- people on small phones
- people who magnify the page
- anyone using a narrow browser window
An iPhone 5 is simply a convenient, well-known device whose logical width is that size. Newer phones are wider in CSS pixels, so they can hide the same overflow. Passing on a modern phone alone is not enough for reflow.
What still uses the iPhone 5
These checks load the page at that small mobile viewport (among other signals):
- Mobile horizontal scrolling
- Mobile zoom and scrolling
- Designed for mobile
- Pinch-to-zoom enabled
- Small mobile text
- Small mobile controls
- Zoom disabled
What uses a modern phone
- The home page overview screenshot uses an iPhone 16 when that capture is available, so the report reflects a current phone.
- The Inspector lets you preview pages on several devices, including iPhone 16, without changing how those checks are scored.