What is SpotDiff?

SpotDiff is a free, browser-based daily spot-the-difference puzzle game. Each day a new scene is generated by AI — vintage cafes, cozy cottages, sci-fi cities, historical interiors, cultural festivals, fantasy realms — and presented as two near-identical images. Your job is to find the differences before the timer runs out. No download, no signup needed.

How to play

• Spot the differences. Two images are shown side by side. Tap or click on each difference you find.
• Beat the clock. A countdown timer adds tension — wrong clicks subtract 5 seconds.
• Use hints if stuck. Hint tokens glow one remaining difference. Earn tokens via daily login, streaks, or referrals.
• Build a streak. Play daily — your streak rewards bonus tokens.
• Replay variants. Each puzzle has multiple variants — finishing one unlocks the next.

FAQ

Is SpotDiff free?

Yes. The puzzles, hints (limited free pool), and progress tracking are free. An optional token bundle is available for players who want unlimited hints.

Do I need to sign up?

No. You can play without an account. Sign-in (magic-link email, no password) is optional and keeps your progress synced across devices.

How are puzzles generated?

Each day's puzzle is created by a custom AI pipeline running on a single GPU. A description prompt is expanded by an LLM, a text-to-image model renders the base image, vision reasoning identifies object positions for differences, and an inpainting model produces the modified second image. Each puzzle is then human-reviewed before publishing.

Why a daily puzzle?

Daily games like Wordle and the NYT crossword fit nicely into a 5-minute coffee break. SpotDiff aims for that same rhythm — visual rather than verbal, playful rather than competitive.

How are differences placed?

A vision-language model identifies natural object positions in the base image, then an inpainting model is used to either modify, remove, or recolor 5–10 elements. The result feels organic — no obvious blur or pasted-on patches.

Can I share or embed puzzles?

Yes. Each puzzle has a unique URL like spotdiffdaily.com/p/<theme-slug>. Share to social media — your stats are auto-included in the share text.

What languages are supported?

The UI is in English. Korean and Simplified Chinese metadata are emitted on each puzzle page for search engines in those regions, and SNS preview cards are localized based on Accept-Language. Full UI translation is on the roadmap.

How can I report a bug or contact you?

Email joohwan82@gmail.com. We read every message.

Recent themes

Some scenes you might encounter: 1920s Parisian art deco cafés, 1930s Dutch canal house living rooms with floral wallpaper, 1940s African-American beauty salons, 1950s American diners with chrome stools, 1970s Tokyo karaoke bars, 1980s VHS rental stores, contemporary Japanese minimalist interiors, cyberpunk Seoul rooftops, dragon hoard caverns, alien desert bazaars, and many more. Browse all 300+ puzzles in the archive.

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