Adele later collaborated with famed musician and producer Dan Wilson on completing "Someone Like You" which was one of the final songs composed for the album. Prior to meeting with Wilson, Adele said she wrote some of the lyrics using her acoustic guitar. The two sat around the piano for two days and brainstormed various melodies and lyrics, and ultimately decided to keep the musical production sparse: "We just wrote it on the piano and then we recorded it when it was written. It wasn't sort of like recording it and listening to it thinking 'where can we go next?' It was really old school." During an interview with Billboard, Wilson stated that while writing the song, they wanted to make it as personal as possible. He added "We didn't try to make it open-ended so it could apply to 'anybody.' We tried to make it as personal as possible. She may not have had a melodic hook or a specific lyrical idea, but she always knew what she wanted to say. She definitely had a master plan." The song was recorded at Harmony Studios in West Hollywood, California with Wilson playing piano. Philip Allen engineered in the studio. The mixing was done by Tom Elmhirst and Dan Parry while the mastering was finished by Tom Coyne.
"[...] 'Someone Like You,' the stirring, somber closer in which Adele goes to visit a former love (with high hopes of a reconciliation), only to discover he has not only moved on with his life, but is in a much better place. And though she's heartbroken, she puts on a brave face, stubbornly proclaiming she'll find someone just like him, even if she knows that she never will. And that conclusion makes you ache not only because it's so daunting, but because it's so real. We've all felt that way, tried to trick ourselves into thinking that any other outcome was possible. In Adele's music, much like life, there are no happy endings." – James Montgomery of MTV News talking about "Someone Like You".
According to sheet music published at Musicnotes.com by Sony Music Publishing, "Someone like You" is a pop and soul song with a slow tempo of 67 beats per minute. Written in common time, the song is in the key of A major. Adele's vocal range spans from F#3 to E5 during the song. A slow, plaintive ballad pairing Adele's voice with a looping piano line, "Someone like You" is the lyrical opposite of "Rolling in the Deep" on which the singer narrates coming to terms with the end of the relationship: "Nevermind, I'll find someone like you/I wish nothing but the best for you, too/Don't forget me, I beg/I'll remember you said/Sometimes it lasts in love, but sometimes it hurts instead." According to Sean Fennessey of The Village Voice, the singer's "nuanced" voice goes up a full octave and "into a near-shrieked whisper" as she sings parts of the chorus. However, she "rebounds and gathers herself", and her voice descends into its fuller and more melancholy state. Critics praised its introspective lyrics and maturity. "Someone like You" has been compared to the song "Hometown Glory" (2008) from the album 19. John Murphy of MusicOMH said that the song "casts Adele as the spurned lover, turning up outside her ex's house, now moved on and settled down, begging for a second chance." According to Aamir Yaqub of Soul Culture, "Talking of a lost love, this an extremely touching track with a vocal performance that makes the narrative almost tangible ... It really captures the experience of the story and puts it across in both a credible and incredible fashion." Camreon Adams of Herald Sun called the song a "spine-tingling sparse piano ballad."
Lyrically, the song talks about the end of Adele's first "real relationship" with her long-time friend and lover and it shows her confronting his marriage. At the beginning of the song, she sings the lines "I heard that you're settled down/That you found a girl and you're married now. I heard that your dreams came true/Guess she gave you things I couldn't give to you" with a softly voice and accompanied just by a simple piano melody. The lyrics of "Someone like You" are talking about what once was and what could have been as stated by a writer of Daily Herald. Finding the strength to bounce back from hardship and heartache, Adele sings the lines, "Never mind, I'll find someone like you. I wish nothing but the best for you, too/Don't forget me, I beg, I remember you said/Sometimes it lasts in love but sometimes it hurts instead." Talking about the meaning and the composition of the song, Jer Fairall of PopMatters said: "The song's subject—Adele mentally addressing an old lover who has since found happiness elsewhere—is familiar, but the detail she colors it with are vibrantly tactile and resonant, from the sense-memory setting of 'we were born and raised in a summer haze' to her recollection of his cruel kiss-off line 'I remember you said, 'sometimes it lasts in love and sometimes it hurts instead'' and how she comes to take solace in the statement as an empowering mantra
"Someone Like You" was written and produced by Adele and American songwriter and producer Dan Wilson. It was one of the last written for 21. The track, which epitomizes the lyrical content of 21, summarizes the now defunct relationship that the record is all about. Adele has openly discussed the genesis of it saying, "Well, I wrote that song because I was exhausted from being such a bitch, with 'Rolling in the Deep' or 'Rumour Has It' ... I was really emotionally drained from the way I was portraying him, because even though I'm very bitter and regret some parts of it, he's still the most important person that's ever been in my life, and 'Someone Like You,' I had to write it to feel OK with myself and OK with the two years I spent with him. And when I did it, I felt so freed."
Adele revealed that she was struggling emotionally when she composed it: "When I was writing it I was feeling pretty miserable and pretty lonely, which I guess kind of contradicts 'Rolling in the Deep'. Whereas that was about me saying, 'I'm going to be fine without you', this is me on my knees really." She discussed further the inspiration of the song: "I can imagine being about 40 and looking for him again, only to turn up and find that he's settled with a beautiful wife and beautiful kids and he's completely happy... and I'm still on my own. The song's about that and I'm scared at the thought of that."
Adele had said that she began writing it on her acoustic guitar in the wake of the break-up of her 18-month relationship with the 30-year-old man she thought she would marry. A few months after their split he was engaged to someone else. "We were so intense I thought we would get married. But that was something he never wanted... So when I found out he does want that with someone else, it was just the horrible-est feeling ever. But after I wrote it, I felt more at peace. It set me free... I didn't think it would resonate... with the world! I'm never gonna write a song like that again. I think that's the song I'll be known for." She also said that "I wrote that song on the end of my bed. I had a cold. I was waiting for my bath to run. I'd found out that he'd got engaged to someone else