Sequencers, also known as music sequencers or audio sequencers, are devices or software applications that are capable of recording, editing or playing back music. The process requires handing both performance and note information through different forms. 

Music sequencers can have several classifications. One of them makes reference to the way data is handled. Within this classification, sequencers divide into MIDI data on MIDI sequencers, CV/Gate on analog sequencers, automation data for mixing automation on DAWs, as well as audio data on audio sequencers. 

Audio sequencers can fall under another categorization, which includes loop-based music software, phrase sampler, a digital audio workstation, beat slicing, and tracker.

In loop-based music software, the pitch/time manipulation allows the user to operate audio samples with MIDI data. In a phrase sampler, users are able to remix or compose tracks by sampling long pieces of a song and then rearranging the parts on grooveboxes. DAWs allow the user to record, edit and playback digital audio. Beat slicing users are able to limit a drum loop sample by slicing beats and then rearranging them on samplers. Trackers allow users to insert sample players into the software music sequencer. 

There are several types of sequencers, including realtime sequencers, analog sequencers, step sequencers, and software sequencers.

Realtime sequencers record musical notes in real-time and then playback these musical notes with a specific tempo, quantization and pitch. Realtime sequencers are capable of editing mixes with a punch in and punch out features. Analog sequencers play the musical notes that are determined by knobs and sliders. Analog sequencers are commonly used to create minimalistic phrases. Step sequencers enable users to enter each musical note without a specific timing so that they can be altered further on. Software sequencers offer functionality features. When using software sequencers, users are able to control the device by using a MIDI controller or a graphical interface.