Mobile app design critique: five startup apps reviewed

Executive overview

Most early-stage mobile apps fail on design basics — not functionality. Poor touch targets, confusing CTAs, and untested flows are the most common culprits.

YC's Aaron Epstein and Glide CEO David Siegel walk through five real startup apps, diagnosing specific design failures and wins in real time.

The fastest way to improve your app is to watch one real user try to complete a task.

Core design principles

• Match platform standards (iOS/Android) — non-standard patterns cost you user trust
• Design for physical context: thumbs, movement, lighting conditions
• Every interactive element must be at least 60px square for reliable thumb use
• Animation helps users track state changes instead of hard cuts
• Respond to taps immediately — a one-second delay is nearly as bad as no response

Pearls — medical reference app

• Strong fuzzy search: misspelled "finasteride" and still returned correct results
• Inline web browser keeps users in-app rather than bouncing them out
• Uses native iOS navigation push — correct and expected
• Star rating control too small for reliable thumb interaction
• Expandable sections lacked a disclosure indicator (arrow or chevron)
• Overall: high bar for the category — contemporary, functional, well-considered

Blue Dot — EV charging finder

• Gets users to the core value immediately: map with nearby stations on launch
• No availability status shown on map icons — users tap seven times and get nothing
• Brand named "Blue Dot" but logo color is green — color in a brand name should match
• Company logo on the main screen is unnecessary; the user is already in the app
• Tapping a station revealed no CTA until a subtle panel was expanded — add a visible button
• Route CTA and Start Charging CTA share the same color; secondary action should be neutral gray
• Suggestion: put one user in a car, mount the app on the dash, and observe

Duffel — college campus snack delivery

• Eccentric orange design with emoji quick-scroll sidebar is novel but disorienting
• Tapping a food item in a preview should scroll directly to that item — it didn't
• No confirmation shown after adding items to bag; unclear if action succeeded
• Gamification (rank-up, Duffel Cash) interrupts checkout before a first order is completed
• Categories need simplification: replace the emoji sidebar with 4–6 clear top-level categories
• Distracted hungry users require an even more frictionless path to purchase

Bold Voice — English accent coaching app

• Onboarding asked too many questions including market research ("how did you hear about us?") — cut half
• Design quality visibly drops from onboarding into the lesson interface
• Primary audio interaction (hear the sound) uses a dark icon on a dark background — too subtle
• Smart default: opens directly into a lesson rather than a generic homepage
• AI feedback on pronunciation worked clearly and lesson format was easy to follow
• Progress summary (what you did well / didn't) plus bookmarking are good retention features

Eden Care — group healthcare management (Africa)

• Web app wrapped as a mobile app — reveals itself through multiple loading screens and non-native tab bar behavior
• Tab labels like "Health and Wellness" wrap to two lines; simplify to single short words (e.g., "Health")
• Homepage leads with a step counter — not the primary job-to-be-done for a healthcare access app
• Find Care section felt incomplete: shows addresses with no clear next action
• App is mostly informational — closer to a brochure than a tool with real interactions
• Mobile advantage unused: location data could surface nearby facilities automatically
• Tap targets losing inputs — any response over one second erodes trust