We want to test mobile page previews — a bottom sheet that appears when a reader taps a blue link, showing a thumbnail, lead paragraph, and an option to open the article — on mobile web article pages. This is an experiment: we will deliver it to a subset of readers via an A/B test, collect usage data for approximately one month, and then turn the experiment off. If results are encouraging, a follow-up project may scale the feature to production.
Design
Designer: @JScherer-WMF
Designs are in T420349
Background
Page Previews (Popups) has been a successful desktop feature for years, showing a tooltip-style preview with a thumbnail and lead paragraph when the reader hovers over a link. The feature is deployed on all Wikipedias and is enabled by default for anonymous users and new accounts. Mobile web has no equivalent — tapping a link navigates immediately.
The mobile apps have their own page preview implementations and have seen positive feedback (see slides). This experiment brings a similar experience to mobile web, using a bottom sheet pattern appropriate for touch interaction rather than the desktop hover-triggered tooltip.
Approach
User flow
- Reader is viewing an article on mobile web
- Reader taps a blue link in the article body
- Instead of navigating immediately, a bottom sheet slides up showing:
- Page image (thumbnail) where available?
- Article title
- Article summary, truncated if needed
- "Open article" button to navigate to the full article
- Reader can dismiss by tapping the X button or tapping outside the sheet
Technical components
- New module in ReaderExperiments extension, with lazy-loading to avoid payload cost for readers who don't interact with links
- Link tap interception on mobile article pages — prevent default navigation for qualifying links and show the preview instead
- Bottom sheet UI component (built locally in ReaderExperiments, or potentially upstream in Codex)
- Lightweight client for the REST Summary API (/api/rest_v1/page/summary/{title}) — same data source as desktop Popups, but independent code with no dependency on the Popups extension
- Experiment instrumentation (funnel: link tap → preview shown → article opened from preview → preview dismissed)
Link filtering
Not all links should trigger previews. At minimum:
- Only links in article body text (exclude navboxes, infoboxes, hatnotes, see-also sections, etc.)
- Only links to article namespace (exclude talk pages, categories, special pages, etc.)
- Only blue links (exclude red links to non-existent articles)
The exact filtering rules should be determined during development and may warrant a subtask.
Experiment Design
Type: A/B test via the Test Kitchen framework within the ReaderExperiments extension
Duration: ~1 month of data collection
Target wikis: English, Italian, Polish, Arabic, Vietnamese, French
Audience: Logged-out mobile readers (specifics TBD)
Control: Current experience (tapping a link navigates immediately)
Treatment: Bottom sheet preview on link tap
Success Metrics
21d logged-out reader retention
Open Questions
- Which links should trigger previews? See "Link filtering" above — needs a concrete decision.
- Bottom sheet component: build from scratch in ReaderExperiments, or propose upstream in Codex? If Codex, what's the timeline impact?
- How should the preview handle missing data? (Articles without a page image, very short lead paragraphs, etc.)
- What is the fallback if the API request fails or is slow? Loading state, timeout behavior? Or just go straight to the linked page?
- What existing link tap behaviors on mobile article pages could be affected by intercepting link clicks? Known cases include: reference/footnote drawers (MobileFrontend), image viewer (MMV), edit section links, hash/anchor navigation, and external links. The link tap interception logic must carefully exclude all of these.
Links
- Mobile app page previews feedback
- Page Previews (desktop): https://www.mediawiki.org/wiki/Page_Previews
- REST Summary API: https://en.wikipedia.org/wiki/Special:RestSandbox/wmf-restbase#/Page%20content/get_page_summary__title_
