Thumbnail Readability Checker
Preview your video thumbnail at the small sizes viewers actually see on phones, desktops and TVs, and check that the text is big and contrasty enough to read.
Economics
- Pricing example
- $12 lifetime (free: 3 checks a day)
- Daily math
- 2 sales a day x $12 = $24/day.
- Target if you hit the daily math
- Target: $550 - $750 / month if the daily math is hit
Audience and urgency
Audience: YouTubers, video editors and thumbnail designers.
Urgency: Thumbnails are designed full-screen but seen as small tiles, where thin or low-contrast text becomes unreadable and the duration badge covers a corner. Creators only notice after publishing.
MVP scope
- ✓ Upload a thumbnail and preview it at typical feed, sidebar, search and TV tile sizes in light and dark mock layouts
- ✓ Contrast check on a text area the user selects (WCAG contrast ratio)
- ✓ Blur/squint test and a warning when key content sits under the duration-badge corner
- ✓ Compare up to 3 variants side by side
- ✓ Runs entirely in the browser; Stripe Payment Link unlocks unlimited checks
Omitted features
- - Do NOT predict click-through rates or claim performance gains
- - Do NOT copy any platform's interface pixel for pixel; use generic mock layouts
- - Do NOT upload thumbnails to any platform
Suggested stack
- Frontend
- React + Tailwind CSS + HTML canvas
- Backend or API
- None: browser-only
- Payments
- Stripe Payment Links or Lemon Squeezy
- Hosting
- Vercel or Netlify (free tier to start)
Repository metadata
- Blueprint ID
thumbnail-readability-checker- Category ID
creator_tools- Monetization ID
one_time
Day-one distribution
Channels
- Reddit r/NewTubers and r/youtubers
- Thumbnail designer communities on X (Twitter) and Discord
- Free single-check page
Reddit strategy
Post before/after examples of your own thumbnails at small sizes and link the free checker.
Cold outreach or directory hook
Give free lifetime licences to 10 thumbnail designers who share it with their clients.
Search keywords
thumbnail preview tool, test youtube thumbnail on mobile, thumbnail text readability
One-shot master prompt
Build a browser-only "Thumbnail Checker" in React with Tailwind CSS and canvas. Core requirements: 1. Upload up to 3 images (1280x720 recommended; warn on other ratios). Show each in generic mock layouts: mobile feed tile, desktop grid tile, sidebar suggestion, search result and TV tile, in light and dark themes, at realistic pixel sizes. 2. Text-area contrast: user drags a box over text; compute the dominant foreground/background colours and the WCAG contrast ratio, with pass/warn labels. 3. Blur test (CSS blur at 2 levels) and a bottom-right overlay showing where a duration badge usually sits, warning if detected edges/text fall inside it. 4. Side-by-side comparison view of up to 3 variants at the smallest size. 5. Free: 3 checks per day (localStorage counter); Stripe Payment Link ($12) unlocks unlimited checks via a licence code. No images leave the browser.
Comparable products
Published 2026-10-08.
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