Rainbow received widespread acclaim from
music critics. At
Metacritic, which assigns a normalized rating out of 100 to reviews from mainstream critics, the album has an
average score of 81 out of 100, which indicates "universal acclaim" based on 27 reviews. 's "
Old Flames Can't Hold a Candle to You", featuring guest vocals from Parton herself (
pictured), was hailed by one critic as
Rainbow's most powerful moment. Brittany Spanos of
Rolling Stone gave
Rainbow four stars out of a possible five and wrote: "On her excellent comeback record,
Rainbow, Kesha channels that drama into the best music of her career – finding common ground between the honky-tonks she loves (her mom is
Nashville songwriter
Pebe Sebert) and the dance clubs she ruled with hits like '
Tik Tok' and '
Die Young', between glossy beats, epic ballads and grimy
guitar riffs. In the process, she also finds her own voice: a freshly
empowered, fearlessly feminist
Top 40 rebel." Spanos also noted the noticeable departure from the electropop sound of Kesha's first two albums, writing, "Kesha used to sing about partying with rich dudes and feeling like
P. Diddy.
Rainbow is full of sympathetic (if at times cloying) prisoner metaphors and therapist clichés [...] Across the board, she achieves a careful balance of her diverse musical selves: The
gospel-tinged 'Praying' takes the high road by wishing the best to the people who have hurt her, and 'Woman' is a blissfully irreverent, proudly self-sufficient
retro-soul shouter backed by
Brooklyn funk crew
the Dap-Kings." She also stated that the album's "most powerful moment" is the singer's cover of
Dolly Parton's "
Old Flames Can't Hold a Candle to You", saying, "Parton herself helps out on guest vocals. But this isn't some
Grand Ole Opry homage. Kesha flips and filters it through her dreamy vision, turning the sweet tune into rousing rockabilly until the standard sounds refreshed and vividly modern, battle-tested and born again. Just like the woman singing it." In an equally favorable review, Hilary Weaver of
Vanity Fair described
Rainbow as "a blatant, angry response to the singer's battle with a legal system that has left her feeling frustrated and trapped as an artist—but also a powerful pop album that earns the anticipation", writing: "This is an unapologetically open and honest Kesha we have never heard before—her voice is still recognizable but not as poppy and more focused with a message she wants her audience to hear loud and clear. She seems to come closest to directly referencing Dr. Luke once, as 'the
boogeyman under [her] bed' in 'Letting Go'; the album is a more general, vocal proclamation against anyone who has wronged her in the past. This is Kesha's story, but it’s also the response that any woman in the
Trump era of
locker room talk might want to blast in her car on a particularly frustrating day." She also described Kesha as being in a "far different place than when her last album was released", calling her a "symbol of women standing up against
patriarchal forces keeping them down" and writing: "It lends an automatic weight to
Rainbow that Ke$ha might not have been able to shoulder—but Kesha, at least as she appears on this album, is up to the challenge." Willman also lamented that the moments where Kesha expresses glimpses of her previous electropop "ridiculousness" on the album "[feel] refreshing and, just maybe, even more authentic. Not that you'd want her to push past her pain prematurely, but when it comes to the writing part, Kesha just happens to still be cleverer at playing koo-koo than guru."
Accolades Rainbow appeared on several publications' year-end lists for 2017, as well as decade-end lists. ==Commercial performance==