Exai is the eleventh studio album by British electronic music duo Autechre. It was released on 7 February 2013 through Warp Records, with physical versions arriving on 5 March 2013. Prior to the release of NTS Sessions 1–4, Exai was Autechre's longest album.

Sean Booth and Rob Brown experimented with something they call "the system", a large network of software and synthesisers, during the creation of Exai. Critics responded generally positively to the album, noting its complexity and its use of sounds from previous albums. Some criticised the selection of tracks on the album and their length. Exai was followed by a companion EP named L-event which released on 28 October 2013.

Brown and Booth, the duo that make up Autechre, released their first song, Cavity Job, in 1991. Their first album, Incunabula, was released in 1993 and became a surprise success. Throughout their discography, the duo gradually moved into less melodic and more experimental and glitchy music, notably with such releases as Confield, Untilted and Quaristice. Critics have described their newer sound as cold, distant and complex.

Brown and Booth have stated that they primarily compose their newer music utilising "the system"—a large network of synthesisers, software and other digital processes built primarily in Max. The duo have said in later interviews that the process is not entirely generative. Instead, human input is still required to make changes and "guide" the system during track creation.

For Exai, the duo decided to move away from MIDI, which was used during the recording of Quaristice, stating that it "wasn't quite what [they] wanted to be doing". Exai and its tracks were a product of trial runs with the new system, subsequently processed and edited into completed tracks. In an interview with Resident Advisor, Booth stated that Exai was discussed as a potential project at least a year before its release. According to Booth, most of the tracks were two or three years old when the album came out.

Exai has been described as electronic, experimental, IDM, abstract and ambient. Exai is spread across 17 tracks, making it a double album. Compared to Oversteps, one critic noted Exai was a lot more complex and "intelligent". Andy Kellman of AllMusic commented that many of the tracks on Exai were thrilling, and noted their accessibility. Kellman discussed tracks such as "recks on", calling it crisp, industrial and a hybrid of beats and bass; he also said that it was among one of the heaviest tracks Autechre had produced. Reviewing Exai for BBC Music, Chris Power called the track "Flep" a unique breakbeat-powered track. The longest track on the album, "bladelores", is an echoing atmospheric track that contains a "wave of pads" surging throughout.

In a review for The Quietus, Charlie Frame called the ten-minute track "irlite (get 0)" a battle between a sub-bass and a variety of random synth stabs. Frame also discussed "bladelores", calling it a highlight of the album. The track is made up of gradually slowing beats, trance-like chords and "gritty little acid squiggles", after which it becomes more ambient before it gets "[pulled] back under" and put "back into the boggy marsh". Frame also compared the track to "Cichli" and "Garbagemx36", two previous Autechre songs, in terms of its structure. Discussing Exai for Pitchfork, Grayson Haver Currin stated that the track "T ess xi" made use of "fluorescent soul keyboards" as a basic building block in its composition. Currin also discussed "deco Loc", describing how the duo used cut-up vocal samples and other repurposed sound which created appealing soundscapes and atmospheres.

Lee Wang of Slant called the album's closer "YJY UX" a moody and empty ambient track featuring "groaning" basslines. Wang also noted "T ess xi", a track reminiscent of Chiastic Slide. Andrew Ryce of Resident Advisor compared the melody of "jatevee C" to Incunabula, and characterised the rhythm of the track "tuinorizn" as stuttering dubstep. Josh Becker of Beats Per Minute called the song "cloudline" a "malformed ode to trip-hop". Becker also compared "Fleure" to "Pulk/Pull Revolving Doors" by Radiohead, both exemplifying the genre of glitch music.