Brady and Les created several new songs for this set, and the enjoyable experience prompted them to intermittently collaborate throughout the year, eventually accumulating enough material for what later became 1000 gecs.

[5] With Brady being in Los Angeles and Les in Chicago, they stated that around 80 percent of the album was done via email,[5] with them sending Logic Pro X files between them.

[5] Her vocals are exclusively pitched-up, "nightcore style", due to her gender dysphoria, since she couldn't listen to her own voice.

In August 2019, 100 Gecs released the album's instrumentals, stems, and a cappella vocals for free download.

[12] 1000 gecs is a genre-hopping album, generally described by Pitchfork as experimental pop[13] and by Sputnik as bubblegum bass.

[14] According to Will Pritchard of The Independent, the album helped to consolidate the eclectic 2010s "hyperpop" style by taking the genre "to its most extreme, and extremely catchy, conclusions: stadium-sized trap beats processed and distorted to near-destruction, overwrought emo vocals and cascades of ravey arpeggios.

[13] Similarly, Fred Thomas at AllMusic described it as being "jittery, ridiculous, and perpetually short-circuiting" but also "a fine-tuned and controlled pop product.