コイントス

Open the site in any modern browser, then click the blue "Flip" button in the center of the page or press Space/Enter to start a flip; the coin animation runs for ~1.2 seconds and the result (Heads or Tails) appears in the large result panel. For multiple flips use the "Flip 10" quick button or the batch input field labeled "Flip N" (type a number then press "Flip"). Toggle sound with the speaker icon and view recent results by clicking "History"; no signup or account is required and everything happens in your browser.

Yes — you can export a single visual result as a PNG snapshot (.png) using the "Download PNG" button, or create an animated short showing multiple flips as an animated GIF (.gif) with "Download GIF". Numerical results and timestamps export via "Export CSV" (.csv) or "Export JSON" (.json); CSV files are UTF-8 and named like flips_20260710_1532.csv. Typical sizes: a single PNG is usually 50–250 KB, a 10-flip GIF is 200–800 KB; very long GIFs (>200 frames) are not recommended due to CPU and memory on mobile devices.

On modern browsers we use window.crypto.getRandomValues (Web Crypto API) to generate unbiased, cryptographically-strong random bits for each flip; if the browser lacks Web Crypto (very old browsers) we fall back to Math.random, which is less robust. There is no seeding option or reproducible sequence — every flip is independent and results are not stored on a server by default. If you need deterministic or reproducible sequences for testing, use a local script (Python or Node) instead, as this tool does not support custom seeds.

Use the batch control labeled "Flip N" to request up to 1,000 flips in a single operation; the default quick option is "Flip 10". The UI will animate the first few flips and then summarize counts (Heads/Tails) — very large batches are throttled to prevent browser freezing, and the tool may pause if the tab goes into the background (browser throttling). Exporting a large batch will produce a CSV or JSON containing each flip with an ISO-8601 timestamp, but the site caps stored history at the most recent 5,000 entries to avoid exceeding localStorage limits.

No signup is required: by default history is stored only in your browser's localStorage and is limited to the most recent 5,000 flip records to stay within typical 5 MB storage quotas. You can clear this local history immediately with the "Clear History" button, and you can export history via "Export CSV" or "Export JSON" before clearing; those exports are generated client-side and downloaded directly to your computer. We also include an optional analytics cookie (toggleable via "Disable Analytics" in the footer) that tracks page usage in aggregate, but it does not contain your flip results.

There are several common causes: iOS Safari and some browsers honor the operating system "Reduce Motion" or prefers-reduced-motion preference which will disable the spin animation; you can change that in iOS Settings → Accessibility → Motion. Audio may be blocked in background tabs or by browser autoplay policies if no recognizable user gesture was detected; ensure you press the "Flip" button directly rather than relying on remote script triggers. Also note the Vibration API is not supported on iOS Safari; Android Chrome supports vibration on user-initiated flips.

First confirm JavaScript is enabled in your browser — the tool is entirely client-side and requires JS. If JS is enabled, try clearing cache and hard-reloading (Ctrl/Cmd+Shift+R) or disabling extensions like ad blockers/privacy plugins that can block scripts or fonts; corporate CSP policies can also block embedded assets and produce a blank area. If you still have trouble, check the browser console (F12 → Console) for errors like "Blocked script" or "getRandomValues is not a function" and switch to a modern browser such as Chrome, Firefox, or Edge for best compatibility.

The History panel shows each flip as an entry with a zero-based index, result (Heads/Tails), and an ISO-8601 timestamp in your local time zone; you can add an optional label per flip before export. Click "Export CSV" to download a UTF-8 CSV with headers (index,result,timestamp,label) named flips_YYYYMMDD_HHMM.csv, or choose "Export JSON" to get a .json array of objects. Export respects the 5,000-entry storage cap: if you have more than 5,000 flips in a session the CSV/JSON contains the most recent 5,000 entries only.

Yes — press Space or Enter to trigger a flip, press "H" to open the History panel, and press "C" to clear history; all interactive controls have visible focus styles and ARIA labels for screen readers. The site respects prefers-reduced-motion and will present a static result instead of an animation when that preference is set. For users who need higher contrast there's a "High Contrast" toggle in the Theme menu that increases color contrast for the coin and result text.

There is no public REST API for flips, but you can embed the flipper UI via an iframe using the provided embed code snippet on the "Embed" page; we recommend an iframe size of 360×480 pixels for best layout. Embedded instances run client-side like the main site, so they do not share flip history with the parent page due to cross-origin protections; postMessage is not currently supported for flip-result callbacks. For programmatic needs use a local script that calls window.crypto.getRandomValues to reproduce the same quality of randomness client-side.

This web tool is optimized for quick, interactive decisions and uses the browser's Web Crypto API where available, which is generally stronger than Excel's RAND() and is comparable to calling /dev/urandom or crypto libraries in desktop environments. For large-scale or reproducible experiments you should use command-line tools (Python's secrets module, OpenSSL, or Node's crypto) where you can control seeds, performance, and output format. The trade-off is convenience: the online flipper is immediate and UI-driven with export buttons, while desktop/CLI tools are more suitable for automation and reproducibility.

The core tool is free to use in-browser with no signup and no watermark on exports; there is an optional donation link in the footer but no subscription or premium tier. Practical limits include the 1,000-flip maximum per batch operation, a 5,000-entry local history cap (due to localStorage size constraints), and a recommendation to keep exported GIFs under ~200 frames for performance reasons. Browser download limits are effectively determined by your browser and OS (browsers commonly handle multi-hundred-megabyte downloads, but animated GIFs from this tool are designed to stay under a few megabytes).