Case Study
ReflectLoop
AI reads between the lines as you journal — surfacing cognitive patterns, thinking styles, and recurring beliefs directly inside your own writing.
Introduction
When a therapist reads a client's journal, they don't just notice what happened — they notice how the writer thinks. Recurring distortions, hidden beliefs, the gap between feeling and explanation. ReflectLoop gives that second pair of eyes to anyone with a notebook.
Year
2025
Role
Product Design · Full-Stack
Timeline
Ongoing
Stack
Next.js, Supabase, Claude
Pattern Detection
Five categories, inline
Click any underlined phrase and a tooltip opens with the pattern name, category, explanation, and a “View all instances” link. Cognitive biases get amber wavy underlines, thinking patterns get blue dots, growth signals get solid green.
Journal scroll
Scrolling through a day's entry. Five patterns highlighted inline with category-specific underlines.
Tooltip interaction
Tapping a highlighted phrase to see the explanation: pattern name, category, and “View all instances” link.
Product Surfaces
The whole product
Landing
Editorial serif headline. For writers who already journal.
Journal
One continuous document per day. AI highlights patterns as you write.
Pricing
Three tiers. Free is genuinely usable.
Insights
274 entries, avg mood 6.3, 847 patterns detected, +233% growth signals. Heatmap, radar, scatter.
Features
Six features: voice-to-text, real-time insights, calendar, photos, pattern timeline. No streaks, no gamification.
Numbers
5
Pattern categories
4
AI passes per entry
847
Patterns detected
+233%
Growth signals
Longitudinal View
A year of writing,
surfaced as evolution
Four tabs — Overview, Patterns, Correlations, Connections. The Patterns tab shows how each thinking style evolves month over month. Growth Mindset increased 230% while Overgeneralization dropped 87% over 12 months.
AI Architecture
Four model passes,
each scoped narrowly
Pattern detection
Claude Sonnet reads the entry and tags spans. Conservative by design — false positives kill trust faster than missed positives.
Cross-entry linking
Compares today's tags against the user's 30-day history. 'I always do this when stressed' becomes legible across entries.
Weekly synthesis
A narrative paragraph — not stats. A paragraph that reads like a friend who's been paying attention.
Quiet by default
Real-time annotations only on Pro. Most writers don't want a presence in the room while they're writing.
Design Decision
The highlight that almost killed writing
Early versions used a heavy yellow underline, like a teacher marking a paper. Testing killed it — people stopped writing freely.
The shipped version uses category-specific typography: soft amber wavy for bias, dotted blue for thinking patterns, solid green for growth. Annotations as marginalia, not red ink.
Stack
Tools used
AI
- Claude (Sonnet + Opus)
- Claude Code
- Anthropic SDK
Design
- Figma
Code
- Next.js 16
- TypeScript
- Tailwind CSS
- Lucide
- date-fns
Infra
- Supabase
- Vercel
© 2025 Hanna de Vries