An incorporation of various pop and rock sub-genres, "Deja Vu" explores themes of nostalgia, heartbreak, and the complexity of moving on from a past relationship.

"Deja Vu" reached the top 10 in Ireland, Australia, Malaysia, New Zealand, Singapore, Canada, Latvia, the United Kingdom, Portugal, and the Czech Republic.

Allie Avital directed the music video for "Deja Vu", filmed in Malibu, California, which shows how the place she is at the moment can be nostalgic and remind her of previous relationships, played by Talia Ryder.

[1] American songwriter and producer Dan Nigro encountered a video of her performing her then-unreleased song "Happier" and was impressed by her vocals, stating, "her voice is insane".

Rodrigo and Nigro co-wrote the song "Drivers License" in July 2020,[2][3] which she released as her debut single in January 2021, to unprecedented commercial success.

[8] Rodrigo began hinting the release of a new song by deleting posts from her Instagram account and sharing cryptic teasers of it in late March 2021.

"[5][6] She posted three clips preceding the announcement, featuring a melting ice cream cone, drifting clouds, and a car being driven along the ocean.

[15][16] In July 2021, Swift, Jack Antonoff, and St. Vincent, the writers of "Cruel Summer", received writing credits on "Deja Vu" for its interpolation of the former.

Mitch McCarthy mixed it at SOTA Studios in Los Angeles and Randy Merrill mastered it at Sterling Sound in New York City.

[28] Writing for The New York Times, Jon Caramanica identified its lyrics as "plain and pinpoint pained", and the "power struggle over who taught who about cool music" as an element reminiscent of Swift as well.

Stereogum's Tom Breihan commended the song's stylistic change of pace from Rodrigo's debut single, describing it as a "giddy, stomping pop banger with a euphoric-singalong chorus", although he also noted their similar subject matter.

[43] Writing for NME, Rhian Daly called "Deja Vu" an illustrious follow-up, and Rolling Stone's Angie Martoccio and Chicago Tribune thought it dispelled any notion that she was going to be a one-hit wonder.

[44][45][46] Quinn Moreland of Pitchfork stated that with "Deja Vu", Rodrigo proved to be "pop music's next heavyweight", complimenting its gratifyingly enmeshing production, and deemed it an audacious and poignant catharsis.

[47] Cragg described the song as an outstanding and lyrically sharp "kiss-off", and writing for Exclaim!, Heather Taylor-Singh opined that it is mesmerizing and "displays the nuances of young love".

[50] Writing for DIY, Jenessa Williams called "Deja Vu" the "perfect bedfellow to Conan Gray's 'Heather'", and described it as a "'don't know what you're missing' fantasy that thrives under chunky drums and painfully relatable snark".

[51] AllMusic's Heather Phares viewed "shades of Alanis Morissette's jagged, jilted younger woman in [the song's] hyper-literate litany of tarnished memories".

Rob Sheffield placed the song at number two, and deemed it the finest and most underrated among Rodrigo's successful releases that year, establishing her as the "pop savant of the moment".

[54] NPR listed it at number 20, and Lyndsey McKenna stated that despite the interpolation, "the track is all Rodrigo: a sharp send-off of an earworm, somehow delivered with both irreverent playfulness and brute force".

[58][a] Upon Sour's release, the song peaked at number three on the chart issued for June 5, 2021, and received a 4× Platinum certification from the Recording Industry Association of America.

Billboard's Andrew Unterberger remarked that Rodrigo displayed typically vulnerable intimacy and bluntness and offered an alternately pleasant and grimy rendition.