The series was originally titled Retreat when it was ordered by FX in August 2021, created by Brit Marling and Zal Batmanglij, who also wrote and directed it.

The show marks the fifth collaboration between Brit Marling and Zal Batmanglij, who had worked together for over a decade, including previously creating the Netflix series The OA.

Development began in 2019, inspired by Marling and Batmanglij's interest in stories about amateur sleuths and young female detectives, as well as how much knowledge Gen Z could gain from the internet.

Marling and Batmanglij had access to an early preview of ChatGPT and incorporated results from their testing of the AI directly into the script.

Brit Marling herself was announced to co-star in a key role alongside her writing and directing duties, playing Lee Andersen.

Principal photography began on February 7, 2022, with filming taking place across Kearny (New Jersey), Utah, and Iceland.

A three-day shoot took place at the Readington River Buffalo Farm in Readington, New Jersey, and a bike-riding scene featuring a glimpse of the Mill Lane Tavern was filmed in Rockaway Boro, New Jersey.

Brit Marling announced on Instagram that September 2, 2022 was the final day of shooting, though the Los Angeles Times reported the series had actually finished filming only in late December 2022.

The show's original August 29, 2023 release date was pushed back due to the 2023 SAG-AFTRA strike, eventually premiering on November 14, 2023.

FX Networks promoted the series with a months-long puzzle involving decoded pages at The Mysterious Bookshop and NFC-enabled rings given out at San Diego Comic-Con that unlocked an online trailer.

Fans created a Discord server called 'Angel Neurosis' to discuss the promotional puzzles, which grew from 30 to 1,000 members during the show's run and hosted weekly watch parties attended by cast and crew members like Zal Batmanglij and Brit Marling.