The vary package in npm is a utility for manipulating the Vary HTTP response header in Node.js applications. It simplifies the process of appending values to the Vary header, ensuring proper caching behavior by downstream proxies and browsers. Using vary helps in indicating which request header fields influence the response, preventing unintentional content delivery of cached content intended for different user agents or configurations. It supports string, array, and even dynamic header adding.
The npm package "vary" has a sporadic release history. It was initially active in 2014 and 2015, with infrequent releases. Releases continued in 2017, then ceased, with no releases from 2018 to July 2025.
The npm package experienced fluctuating download numbers. From February 2024 to July 2025, downloads generally increased, peaking in July 2025 at 188,665,696. August 2025 shows a significant drop, likely due to incomplete data for the current month.
