FAQ
Frequently asked questions
Short answers, matched to what the tool actually does.
Does my image or video get uploaded anywhere?
No. It's read locally with the browser's File API and shown through a local Object URL and canvas. There's no upload endpoint on this site for it to go to. Full detail on Privacy.
What file types can I use?
Common raster images (PNG, JPEG, WebP, AVIF, GIF, BMP) and video, using whatever codecs your browser supports. SVG is deliberately not supported.
What does "Safe" mean?
The Subtitle's current position and size don't intersect a platform's loaded reference regions, and clear a small margin around them. It's a geometry check against the evidence currently loaded — see How it works — not a guarantee that your caption will be visible for every viewer.
Why could a position be Safe here but still get covered on my phone?
Real platform UI shifts with app version, device, account state, video length, and features like pinned comments or end screens. The reference regions in this tool are drawn from specific, documented measurements — a particular device, app version, and set of samples, described in each platform guide — not from every possible configuration.
What does "Find safer position" actually do?
It searches for the nearest position — same width and height as your current Subtitle, never resized — that clears every loaded platform's regions at once. If no such position exists at the current size, it tells you that directly and suggests resizing, instead of returning something that still overlaps.
Why do Shorts, Reels and TikTok give different results for the same position?
Because their UI genuinely sits in different places. Each platform's guide explains what typically overlaps a subtitle there and exactly what's loaded for it.
Does a Safe result guarantee my caption will never be covered?
No — and this tool doesn't claim that. It checks against specific, currently loaded evidence. Platform UI can change, and not every device or app version has been measured. Treat Safe as "clears what we've currently verified," not as a universal guarantee.
What does "Demo Data" mean?
Synthetic, made-up regions — not measured from any real platform — used so you can try the tool immediately without waiting on evidence. It's labeled MOCK / DEMO everywhere it appears in the interface and is never presented as verified. Switch the Data selector to Reference · Organic for the evidence-based regions instead.
Why are some evidence sources marked "pending" instead of active?
Evidence status (current / pending / legacy) is tracked separately from how good a measurement is. A measurement is pending when it hasn't yet met this project's bar for production use — for example, missing a specific controlled sample. Only current evidence ever feeds a Safe/Warning/Overlap result or Find safer position; pending and legacy evidence is kept visible but excluded from judgment. The Shorts guide walks through a concrete example.
Is this affiliated with YouTube, Meta/Instagram, or TikTok?
No. This is an independent tool, not built, endorsed, or reviewed by any of those companies. More on About.
Can I check more than a subtitle — a logo, or a call-to-action?
Not yet. The tool currently centers on one shared element (Subtitle). Other element types are a possible future direction, not something available today.
Does this cost anything or need an account?
No. No account, no login, no payment — the tool runs entirely as a static page in your browser.