REAPER is a Windows program created for the arrangement, recording, mixing, editing and rendering of audio. It has a flexible and easy to use control interface that will be easy for amateurs and has enough depth and variations for professionals.

REAPER is designed to help users work quickly and creatively, without any artificial limits on what users can do. REAPER does not have busses, track types, tools, or offline processing. Any track can be a bus, track channels can be sent wherever the user prefers. Drag from one track to another. Sidechaining is also easy by draging a send from its source to a target, then selecting a plug-in to sidechain.

Because REAPER doesn't have track types, you can use an audio gate to write MIDI triggers right on the same track. Or, render a virtual instrument from MIDI to audio as a new take. You can insert MIDI track controls at any point in the signal chain, to control MIDI pan (or anything else) both upstream and downstream of a MIDI plugin.

Every item has handles for fades, snap points, volume, per-take FX, and more, so you can work intuitively without constantly switching tools or keeping track of what mode the mouse is in.

With Free Item Positioning, you can visually arrange any number of media items vertically within a single track to control how the items crossfade and mix together. All processing is non-destructive, so once you have the perfect arrangement, glue and lock the items until you're ready to tweak some more.

REAPER's easy-to-use and sophisticated branching undo system means that you can work with creativity and confidence, knowing that you can get back to any prior state with a mouse click. REAPER can even track your actions right in the title bar so you can always see what you've just done.

Native VST plug-in bridging and firewalling allows you to run REAPER x64 with nearly seamless integration of Win32 plug-ins. Or, on any Windows system, firewall VST plug-ins in their own process space to maximize RAM utilization and protect against plug-in crashes bringing down the whole project. A firewalled Win32 VST plug-in can be configured to use up to 3GB of RAM all for itself, without sharing memory space with REAPER or any other plug-in, on any Windows system.

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.

Related Hardware:
To record audio you will need an Audio Interface: See our review of USB Audio Interfaces here.

New in v5.0.3

• Bugfix for various small issues with LFO's
• Bugfix for functional and cosmetical problems with serial number text edit box
• Bugfix for added support for additional sound sets

New in v5

• Major performance and workflow improvements
• Multiple bugfixes

New in v4.77

• Support for naming sliderXY variables via @sliderx:varname=defval<... syntax
• support for MIDI/OSC action binding
• Improved project tab support for FX
• Improved FX envelope panel undo behavior
• Trim behind mode better handles exactly-overlapping items
• Bugfix for last touched parameter when skipping sliders .
• Bugfix for potential crash with bad timestamps .
• Bugfix for fixed encoding of linear tempo changes in exported MIDI .mid file writing fixed when ticks per QN is configured higher than 64k
• Bugfix for track icon alignment setting .
• Bugfix for setting of no track grouping indicator .
• Bugfix for screenset issues with input FX and hardware FX
• Bugfix for potential for invalid output in certain but rare fades
• Bugfix for start offset adjustment when using take playrates
• Bugfix for hide/restore of input FX windows on tab switch
• Bugfix for invalid render directories/filenames in certain instances .
• Bugfix for moving items with other locked items at same position .
• Bugfix for incorrect latency reporting when changing pin connections

New in v4.73

• Added the elastique v3 pitch shift/timestretch engine.
• Improved Undo for duplicate actions
• Optimized disk writing buffers
• Improved handling of certain low-level mono signals
• Bugfix to extreme stretch logic.
• Bugfix for MIDI Learn
• Various other bugfixes

New in v4.721

• Bugfix for GetSetTrackSendInfo() UI refresh issues .
• Bugfix for toggle states of Humanize/Transpose notes actions
• Bugfix for chat window crash on OSX .
• Bugfix for marker visibility bugs when using take playrates
• Reduced excessive audio locking from many less-often-used actions
• Do not block audio threads when closing/reinitializing MIDI devices
• Reduced excessive locking in track envelope window
• Unfreeze no longer blocks audio from other projects
• Faster performance when using many tracks that are not visible in track list
• Faster/smoother updating when vertical zooming arrange view
• Faster changing of mode for large track counts
• Bugfix for multiple undo points being added when toggling setting
• Bugfix for possible crash when removing take envelopes
• Pitch envelopes that are inactive are properly ignored (and do not use pitch shifting)
• Various other bugfixes and improvements

New in v4.7

• Better Windows 7/8 audio device performance via MMCSS option
• Improved WASAPI support for Windows 7/8
• Restore Project Tabs when restarting Reaper
• Improved performance when working with large track, marker, and region counts
• Various other fixes and improvements, changelog details here

New in v4.62

• Plugin extensions can register MIDI/OSC learn-able actions .
• Plugin extensions can register actions in any section .
• Plugin extensions can register toggle actions in any section
• Bugfix for RenderFileSection() return value
• Bugfix for directory issues .
• Bugfix for Screensets/Layouts shortcut issues
• Allowed localization of toolbar names
• Various other fixes and enhancements, details here

New in v4.611

• Bugfix for menu language pack issue.
• Bugfix for MIDI Editor
• Bugfix for encoding of certain strings with quotes in them (group and comp names).
• Bugfix for decoding of certain (rare) strings.
• Bugfix for GetToggleCommandState2 to work with other sections.
• Bugfix for MIDI text/sysex event get/set support.
• Bugfix for MIDI_SetTextSysexEvt and MIDI_GetTextSysexEvt
• Bugfix for potential crash on exit introduced in 4.61.
• Bugfix for potential UI hang with linear tempo transitions on Win64.
• Bugfix for move segment preserving end values with square points.
• Keyboard shortcut to replace FX preserving routing changed from R to Ctrl+R.
• Bugfix for random noise being possible for unlooped items with negative start offsets.
• Bugfix for JSFX: gfx_arc() drawing
• About box now has option to show only personal or small business use in titlebar for this license type.
• Memory mapped peak files are off by default to save address space/better deal with lost disks.
• Added new (default) option to use audio device reported latency rather than relying solely on ping tests.
• Faster saving, faster loading.
• Bugfix for routing window visual alignment
• No longer unload plug-ins DLLs on exit.

New in v4.61

• Performance improvements and optimizations
• MIDI CC Chase bugfix
• Stability improvements and other bugfixes
• Various other enhancements, here

New in v4.602

• Better ReaScript support including built-in EEL language
• Improved JS functionality, keyboard support
• New JS step sequencer
• MIDI editor filter and selection improvements
• ReaVerb impulse spectrographs
• Various other fixes and optimizations

New in v4.459

• Bugfix for keyboard navigation in FX chains on Windows .
• Bugfix for peakbuilding when changing samples via combo box
• Various other improvements and bugfixes

New in v4.457

• Better MIDI peaks displays in arrange view
• Better inline MIDI editor behavior
• Improved OSC receiving support (actions with values, MIDI, better soft takeover support, etc)
• Other minor changes

New in v4.456

• Better multi-channel track performance for AU and JS plug-ins
• Improved FX drag-and-drop behavior
• Fix for SMPTE LTC generation/sync
• Render improvements for stems/project regions
• Various other bugfixes and improvements

New in v4.454

• MIDI editor multicontext refinements
• Enhanced MIDI import/export
• Improved JSFX scripting
• Various bugfixes and plug-in related optimizations

New in v4.402

• Bugfix for incorrect volume blip when adding sends
• Bugfix for some potential crashes when removing tracks and sends

New in v4.33

• Improved video support including WEBM encoding/decoding
• Big improvements on Project Bay (various bugfixes and improved memory efficiency)
• More bugfixes and enhancements

New in v4.32

• mouseover highlight of current position.
• improved functionality with click/drag to change multiple tracks.
• show MIDI inputs and outputs.
• improved display of MIDI-only sends.
• option (default) to clear automutes on playback start.
• improved updating of arrange when automuting.
• improved new 4.30 fade shape behavior with fully overlapping items.
• avoid creating tiny media items when pencil-drawing with snap enabled.
• improved linear painting in drum modes.
• fixed overdub+autopunch+preroll bug [issueid=4046].
• allow pasting of MIDI events directly in arrange view (adds item, or pastes in existing item).
• fixed incorrect transition from mono to stereo signals with stereo impulses.
• corrected latency immediately after samplerate change.
• improved layout when using large fonts on Windows.
• fixed parent channel not repopulating after adding sends.
• FX browser: optional alternate tree/list layout (doubleclick divider to change).
• ReaStream: added localhost support for win32, improved broadcast support on OS X, improved recent host history.
• Time signatures: fixed adjusting media items when changing time signature numerator.
• added preliminary VLC support for video playback
• added YV12 colorspace support for OS X
• improved bridged-quicktime behavior with mp3 audio (ignores audio rather than crashing).

New in v4.31

• MIDI improvements
• Bugfix and improvement for Crossfade editor
• Changes with the Mouse modifiers:
• Changes with Cursors behaviors
• Various other bugfixes and enhancements, details here

New in v4.21

• Bugfix and improvement for control surfaces
• Bugfix for OSC
• Bugfix for recording and improved latency
• Added actions to insert time and paste items
• Cue ensures correct rendering of .wav files
• Bugfix for MIDI pools
• Bugfix for Project bay autoretain
• ReaScript/API export added
• Transient detection changes

New in v4.13

• fixed effSetSpeakerArrangement on bridged plug-ins

New in v4.02

• Mouse updates:
• added features for restore and marquee zoom, scrub/jog behavior, browser scroll,
• Existing configurations are properly saved
• Ctrl+right-click makes a time selection just like in ver 3.xx
• Assigning mouse click to actions behave properly.
• Other mouse or pointer improvements.
• Project bay updates:
• Allows track listing by name.
• Now shows an error message when users move or copy a file to a target where the same file exists.
• File resolving is used when loading retained items.
• MIDI editor
• Resolved problems when drawing over CC events with snap enabled
• horizontal zoom is now working properly with mouse cursor center, while using timebase that is project-synced.
• Accidental time selections in ruler can now be avoided.
• Negative swing quantize is supported
• Envelopes Updates:
• Initial envelope is editable regardless of editing preferences.
• Transition point can now be added when recording automation while there is no playback.
• Clicking on an envelope point works properly
• MIDI:
• No more stuck notes during looping.
• Renaming a pooled take now renames the other pooled takes.
• More bugfixes and updates are available at the Reaper page.

New in v3.74

• VST:
  more handling for VSTs that resize themselves
  fixed window sizing bug causing some FX to open in a too-small window
  Actions: fixed loop length halve/double actions

• API: fixed support for modifying very short items via certain API functions
• Master track: channel count now reset on new project, able to save in project defaults
• MIDI editor bank/program select: don't sort program banks alphabetically
• MIDI recording: prevent dropped notes in MIDI replace record mode
• Mixer: fx parameter scroll button positioning fixes
• Nudge/set: fixed bug when duplicating grouped items
• OSX: Better performance when updating arrange view while bringing media online
• Project templates: default project template is now stored with relative path in .ini (for config import/export, portable installs)
• ReaControlMIDI: fixed manual text entry of pitch and pan values
• Stability: various small potential memory corruption fixes (thanks, nitpicker!)
• Track locking: fixed unlocking of track not adding undo state
• WINE support: properly detect newer versions of WINE

New in REAPER 3.72:

• MIDI editor:
  moving CCs/events now updates pre-quantized positions
  reduced memory use when opening/closing many editors
  fixed memory leak when reusing MIDI editor and switching between MIDI items
  fixed stuck velocity display on reopening some MIDI editors

• API/ReaScript:
  added SetMediaItemPosition/Length, with the option to suppress screen redraw
  better portability between Windows and Mac (strip Windows newlines)
  API functions for item/marker setting should now perform better on OSX

• Armed actions:
  show special cursor and tooltip only when clicking will trigger the action
  do not cancel armed action on undo

• Feedback routing:
  fixed stopped monitoring with feedback
  decreased memory/CPU use

• Media items:
  disabled "copy loop of selected area" action for MIDI items
  recalculate autocrossfades for beat-based media items when changing time signature
  allow copying loop of selected area when the time selection includes the item end

• Shift+click item selection:
  now use range of clicks rather than range of items
  no longer unselects other items (hold ctrl in addition for this)
  respects option to select all grouped items

• MIDI recording: fixed some overlapping note issues with replace and overdub recording modes
• OGG support: improved stability/playback of corrupted OGG files (libvorbis 1.3.1 bug)
• Performance: Reduced thread locking when recalculating item information
• Shift+click time selection: on now obeys edit cursor moving preferences
• Stability: Improved MIDI note previewing threadsafety
• VST: better resize notification support

New in REAPER 3.71:

• ASIO: requested audio block size: fixed power-of-two rounding mode
• Media items: drawing fix for empty items
• Arc/roundrect drawing: fixed bugs, smaller code
• ASIO: support for requesting audio block size (many drivers will ignore, though)
• Floating toolbar: fixed refresh on update of theme
• MIDI editor: avoid unsafe memory access on undo
• Themes: fixed drawing glitch on docker tabs (and potentially elsewhere) introduced in 3.69