This is the oTAPE Web Deck: about 1,200 lines of plain JavaScript, no libraries. It comes loaded with Gitsem, a C10 single that Mirat Can Bayrak wrote at 24 and recorded again at 42, and plays any .otape you drop here. Files stay in your browser and are never uploaded.

Gitsem by Mirat Can Bayrak, licensed under CC BY 4.0. Source.

A cassette never sounded the same in two players. oTAPE players can now play a tape the way a machine of the era would have: a studio deck, a car stereo, a portable stereo that has seen better days. The sound changes on its way to your speakers. The file stays exactly as it was recorded.

How it's done

1. WobbleNo motor turns perfectly evenly. A slow drift in speed bends the pitch (wow), a fast shiver roughens it (flutter). The player reads the music a hair early or late, moment by moment, so the pitch wanders just as much as it did on that machine.
2. HissEvery tape has its own bed of noise. It runs while the tape runs, between songs and over blank tape too, and stops the moment you press stop.
3. WarmthRecord a tape hot and it rounds off the peaks, the treble first. That gentle squeeze is a big part of why cassettes sound warm.
4. WearOld tape loses its top end, drops out for a split second where the coating has worn thin, and a head knocked out of line smears the stereo picture.

mimetype               application/vnd.otape.cassette
manifest.json          the cassette, sides A and B, the look
audio/
  side-a.m4a           AAC-LC, one continuous take
  side-b.m4a           omitted while the side is blank
artwork/               optional, fixed physical sizes
  cassette-face-a.png
  label-a.png
  jcard-front.jpg  jcard-spine.png
  booklet-01.png …
docs/                  booklet.html, notes.md

{
  "format": "oTAPE",
  "format_version": "1.0",
  "cassette": {
    "id": "550e8400-e29b-41d4-a716-446655440000",
    "title": "Night Drive",
    "type": "C60",
    "side_length_seconds": 1800,
    "created_at": "2026-10-28T22:00:00Z"
  },
  "sides": {
    "A": { "write_protect": "intact", "audio": null },
    "B": { "write_protect": "intact", "audio": null }
  }
}

Pick a length

• C4623 min / side · 65.7 m · 18 µm
• C6030 min / side · 85.7 m · 18 µm
• C9045 min / side · 128.5 m · 12 µm
• C12060 min / side · 171.4 m · 9 µm
• C74

A custom tape is named like a real one: C plus its total length in minutes. Tape length and thickness follow the reel model in Appendix B.3 of the spec.

Snap the tab

Recording allowed:

This isn't DRM. Like the tab on a real cassette, it protects a finished tape from being recorded over by accident, and anyone can tape over the hole.

24 px/mm recommended, 12 px/mm minimum, aspect ratio within ±1%. Shell and label images must be transparent over the window and hub holes, so the player's reels show through.

Cassette faceSVG · 1:1 mm LabelSVG · 1:1 mm J-cardSVG · 1:1 mm Booklet panelSVG · 1:1 mm

07 The reference app

oTAPE Studio.

A three-piece hi-fi for your Mac: the SP-2 CD/MP3 source player and the TU-01 internet radio tuner, both wired into the OT-1 cassette deck. Load your music or tune in a station, press REC, and the tape records in real time. Pause the player and the deck records silence. Save, and you have an .otape file. New in 1.2: tape sound, so any tape can play through a machine of the era.

08 In your browser

Studio,
on the web.

oTAPE Studio Web is a cassette deck that runs in your browser, on any computer. Open a tape or start a blank one, then record onto it in real time from a playlist of your own songs, an internet radio station or any audio input. Save, and you have an .otape file. Nothing to install, no account, and your cassettes and songs never leave your device.