One of the most ambitious early projects was a built on the osu!lazer framework. Developed by JustMangoou, this tool allowed you to view imported replays without launching the actual game. Key features included custom skin support, the ability to download replays (if you were logged in), and rendering replays to video files using FFmpeg . It required .NET 5.0 and an OpenGL ES 3.0 compatible device. While the tool is now deprecated (last updated over a year ago), its legacy remains influential. The developer noted that while the code is "janky" due to IPC with FFmpeg for rendering, the concept of using osu!lazer components to run a lightweight viewer outside the official client was groundbreaking.
Here is a comprehensive guide to the best osu! replay viewers available in 2026. What is an osu! Replay Viewer?
Exactly when Key 1 (Z), Key 2 (X), Smoke, or Mouse Buttons were pressed and released. osu replay viewer
A: Tools like danser-go and o!rdr are widely used and trusted by the osu! community. Always download from authorized sources.
// Draw time progress arc on bottom right const progress = currentTime / totalDuration; ctx.font = "bold 14px 'JetBrains Mono'"; ctx.fillStyle = '#ccdeff'; ctx.shadowBlur = 0; ctx.fillText(`⏵ $(currentTime/1000).toFixed(2)s`, canvas.width-90, 35); One of the most ambitious early projects was
const uploadZone = document.getElementById('fileUploadZone'); const fileInput = document.getElementById('replayFileInput'); uploadZone.addEventListener('click', () => fileInput.click()); fileInput.addEventListener('change', (e) => const file = e.target.files[0]; if (!file) return; const reader = new FileReader(); reader.onload = (ev) => processUploadedJSON(ev.target.result); fileInput.value = ''; ; reader.readAsText(file); ); // drag drop uploadZone.addEventListener('dragover', (e) => e.preventDefault(); uploadZone.style.background = '#1f2e4a'; ); uploadZone.addEventListener('dragleave', () => uploadZone.style.background = ''; ); uploadZone.addEventListener('drop', (e) => e.preventDefault(); uploadZone.style.background = ''; const file = e.dataTransfer.files[0]; if(file && file.type === 'application/json') const reader = new FileReader(); reader.onload = (ev) => processUploadedJSON(ev.target.result); reader.readAsText(file); else alert('drop JSON file plz'); );
// helper: update stats from replayFrames function recomputeStats() totalClicks = replayFrames.filter(f => f.click === true).length; // For better simulation: accuracy based on clicking consistency? we simulate "perfect hit ratio" using click density. // but for visual fun: we assume 95% baseline with a slight variance based on click frequency? // For cleaner demo: each click is considered a "hit" and we calculate an estimated accuracy relative to beat density? // better: mock accuracy = min(100, Math.floor(85 + (totalClicks / Math.max(1, replayFrames.length/5)) * 10)); let clickEvents = totalClicks; let totalFrames = replayFrames.length; let clickDensity = totalFrames ? (clickEvents / totalFrames) * 100 : 0; let mockAcc = Math.min(99, Math.floor(78 + clickDensity * 0.4)); if (mockAcc > 98) mockAcc = 96 + (clickEvents % 3); hitAccuracyEstimate = Math.min(100, Math.max(65, mockAcc)); accuracyStatSpan.innerText = hitAccuracyEstimate + "%"; It required
stands out as one of the most powerful multi-purpose osu replay viewer and analysis programs available today. It serves a dual purpose: a self-improvement tool and a robust cheat detection suite.
Use the command line or GUI to customize shaders and camera angles. Summary of Replay Viewer Features ReplayViewer.com Online Rendering Desktop App Setup Time Customization Performance Varies (GPU) Varies (Browser) Best For Aesthetics Quick Review Frequently Asked Questions