REAPER is a powerful but sensible Windows application designed for the recording, arrangement, editing, mixing and rendering of audio. REAPER provides a flexible but easy to use interface that is equally suited to amateurs and professionals alike.

REAPER is a small and lightweight application (the installer is less than 1 megabyte, which includes many effects and a sample project). REAPER is designed with both processing and user interaction speed in mind.

Basic Features:

• Support for an unlimited number of audio tracks.
• Audio tracks are all fully routable (multiple inputs, outputs).
• Volume, pan controls and envelopes per track.
• Supports audio processing plug-ins (DirectX, DXi, VST, VSTi, and Jesusonic) with automation, easy chain manipulation and editing.
• Pitch shifting and time stretching.
• Fast, reasonable and usable Windows-style UI, working well on both low and high resolutions or multiple monitors.
• ASIO, Kernel Streaming, WaveOut, and DirectSound support for playback and recording.
• Reads WAV, OGG, MP3 and MIDI files, records WAV and MIDI files.
• Can render to WAV, OGG, MP3 if lame is installed.
• Full SMP support (can utilize 2 or more processors).
• Multi-layer undo/redo support.
• User creatable color themes.

Advanced Features:

• Unlimited send/receives per track, with configurable parameters (pre-fx, post-fx, volume/pan adjustment/envelopes, mix to mono, phase, etc.).
• Any track can act as a bus, for routing flexibility.
• Tracks can have one or more (mono or stereo) hardware sends, for analog mixing capability.
• Fully routable/FX-able folder tracks that can contain group tracks.
• Item grouping.
• Ripple editing.
• Grid/snap support with configurable options.
• Markers.
• Unlimited takes per media item.
• Auto punch-in/punch-out functionality.
• Automatic record monitoring modes.
• Selection length granularity options as well as grid snapping.
• Tempo envelope (for grid lines/snapping/ruler), play-speed envelope.
• Project consolidation/export options (for rendering all or parts of any number of tracks to WAV, etc.).
• A UI and architecture that allows you to easily cut loops of many tracks simultaneously, without having to write them to disk.
• Support for plug-in generated media (such as click tracks, etc.).
• Project tempo envelopes for variable tempos in track, grid/snapping that supports variable tempos.
• 64-bit floating point sample pipeline for high quality.
• Advanced recording and monitoring options; examples:
  - You can route multiple tracks (inputs and/or media items) into a bus, and record THAT mixed down version.
  - You can record the input signal, or record the post-FX, post-track-render signal.
  - You can switch recording sources on the fly, even while recording.
  - You can arm/disarm tracks' inputs while playing or recording.

Other Features:

• Human readable, human editable, backwards and forwards compatible project file format.
• Options to build peaks for recorded files on the fly.
• Lots of control for the user to specify where recorded files go, etc., when dealing with many projects.
• Template support to make it easy to load a project template and save it as a new project when you begin.
• Input/output channel name aliasing (why view your inputs as "MOTU 896: Analog 1" when you could have them be "Vocal Mic", etc.).
• Options for automatically backing up project files to alternate paths, time-stamped versions, etc.

New in v3.13

• Action: insert multiple tracks.
• API: added functions: AddProjectMarker, DeleteProjectMarker.
• Automation: new volume/pan envelopes display the current track fader value.
• Crossfades: fixed auto-crossfade when control+drag copying items.
• FLAC: fixed multichannel read support.
• FX chains: automatically increase track channel count when loading FX chains that use more channels.
• Glue: special fade handling when gluing multiple items starting or ending at the same time.
• Mixer: consistent scroll behavior regardless of number of tracks, autoscroll to newly added tracks.
• Master: no reset of master mono/stereo setting after automatically muting on overload.
• Media items: button to display item properties, by default shown only when the item is resampled.
• Media explorer: configurable default-handling of project files, better context menus.
• Media explorer: filter fixes.
• Menus: most commonly used menus can be customized (add/remove actions, submenus, rename menu items).
• Menus: menu customizations can be imported/exported to file.
• MIDI editor: user preference to flash keyboard notes on track input note-on.
• MIDI editor: setting to snap note ends to grid when snap enabled.
• MIDI editor: fixed snapping bug when following project beats and grid is 1/4 note triplets.
• MIDI editor: better keyboard handling in text fields.
• Mousewheel: fixed control+mousewheel for fine slider moves in parameter modulation and send windows.
• Mute/solo: setting via right-click follows selection/grouping unless overridden with shift key.
• Peak building: optimizations (50-150% faster on .wav files in our tests).
• Peaks: when using alternate peak path, put peaks in numbered subdirectories for better performance.
• Peaks: low quality preview peaks during building are now are more consistent with finished peaks.
• Peaks: aborted peak generation removes partial (invalid) peak files.
• Project load: replacing files with different types will scan for the same file type for other missing files.
• Project/template load: current working directory defaults to project/template path.
• ReaScript: added GetTrackState, expanded html help, set undo point after script executes.
• ReaScript: capture Python compile-time and run-time error messages for display.
• ReaScript: fixed get/set of integer-type track, item, or take parameters.
• Take names: automatically focus take name field when displaying item properties.
• TCP: Drag and drop routing now autoscrolls.
• TCP/Mixer: autoscroll to tracks selected via action or control surface.
• Track icons: optionally set all tracks to the same width when any track icons are used.
• Undo system: greatly reduced memory use when loading undo history from file.
• VST: fix for bridged/firewalled plug-ins with track controls visible.
• VST: added MIDI output mode to merge output with input (for groove players, arpeggiators, etc.).
• VST extensions: support for effString2Parameter (mostly for readable manual editing of envelope points).
• VST MIDI: fixed hanging note bug from synthedit and possibly other plugins that generate MIDI.
• Windows: drag and drop of files out of REAPER now better supports unicode characters.
• Windows: try to prevent bad plugins from quitting REAPER.
• x64: ReWire support (master/mixer only).