SnapFree interactive visual diff tool.
Instant image comparison.
Upload two images to compute pixel-by-pixel visual diffs. Highlighting regressions in red, handling dimension shifts, and running 100% in-memory with zero signup.
How Snap Visual Diff Works
Built on Snap's production comparison engine (@snapdrift/compare-core), designed for deterministic visual regression testing.
Pixel-by-Pixel Precision
Compares images pixel-by-pixel, highlighting every changed coordinate in bright red so subtle CSS shifts, padding changes, and color regressions stand out immediately.
Unequal Dimension Handling
Avoids brittle dimension mismatch crashes. A bounded union canvas compares common coordinates and flags added or removed page areas seamlessly.
Ephemeral Comparison Privacy
Your uploaded images are compared in isolated ephemeral compute and temporary objects are deleted after the diff is returned; a one-day lifecycle rule cleans up if processing is interrupted. No database entries are created.
Bring Visual Regression into Your Pull Requests
Tired of manually uploading images? Connect Snap's hosted provider to run visual diffs automatically on every pull request with centralized baselines and a full review dashboard.
Frequently Asked Questions
Common questions about Snap's visual diffing engine and capabilities.
Do I need an account to use the visual diff tool?
No. The interactive visual diff tool is completely free and works with no account, signup, or API key.
What image formats and sizes are supported?
PNG, JPEG, and WebP images up to 5MB each. The tool automatically normalizes your uploads into crisp PNG buffers for exact pixel-by-pixel comparison.
What happens if the two images have different dimensions?
Unlike basic diffing engines that crash on dimension mismatches, Snap uses a bounded union canvas approach. Any expanded or shifted regions are automatically highlighted as visual changes.
Are my uploaded images stored or logged?
No. All comparisons are executed purely in-memory. Your images are never stored in S3, never saved to disk, and never persisted to any database.
Can I automate visual diffs in my GitHub Actions CI pipeline?
Yes! This exact engine powers Snap's Hosted Visual CI and the open-source SnapDrift tool (snap.i2dev.com/snapdrift). You can run automated visual regression on every pull request with hosted baselines and pull-request comments.